diff --git a/pom.xml b/pom.xml
index cde601d..062c8dc 100644
--- a/pom.xml
+++ b/pom.xml
@@ -95,7 +95,7 @@
 		<dependency>
 			<groupId>junit</groupId>
 			<artifactId>junit</artifactId>
-			<version>4.11</version>
+			<version>4.13</version>
 			<scope>test</scope>
 		</dependency>
 		<dependency>
@@ -137,7 +137,7 @@
 		<dependency>
 			<groupId>org.slf4j</groupId>
 			<artifactId>slf4j-api</artifactId>
-			<version>1.7.25</version>
+			<version>1.7.30</version>
 		</dependency>
 		<dependency>
 			<groupId>eu.clarin.sru.fcs</groupId>
@@ -182,7 +182,7 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-surefire-plugin</artifactId>
-				<version>2.22.1</version>
+				<version>2.22.2</version>
 				<configuration>
                     <useSystemClassLoader>false</useSystemClassLoader>
 					<excludes>
@@ -193,7 +193,7 @@
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-compiler-plugin</artifactId>
-				<version>3.7.0</version>
+				<version>3.8.1</version>
 				<configuration>
 					<!-- <verbose>true</verbose>
 		          	<fork>true</fork> -->
@@ -201,7 +201,6 @@
 					<compilerVersion>2.0</compilerVersion>
 					<source>${java.version}</source>
 					<target>${java.version}</target>
-					<argLine>-Xms512m</argLine>
 				</configuration>
 			</plugin>
 			<!-- <plugin>
diff --git a/src/main/java/de/ids_mannheim/korap/query/parse/fcsql/FCSSRUQueryParser.java b/src/main/java/de/ids_mannheim/korap/query/parse/fcsql/FCSSRUQueryParser.java
index c4d0fa1..3babf9c 100644
--- a/src/main/java/de/ids_mannheim/korap/query/parse/fcsql/FCSSRUQueryParser.java
+++ b/src/main/java/de/ids_mannheim/korap/query/parse/fcsql/FCSSRUQueryParser.java
@@ -2,6 +2,7 @@
 
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.List;
 
 import de.ids_mannheim.korap.query.object.KoralContext;
@@ -125,7 +126,7 @@
     private KoralGroup parseWithinQuery(QueryWithWithin queryNode)
             throws KoralException {
         KoralGroup koralGroup = new KoralGroup(KoralOperation.POSITION);
-        koralGroup.setFrames(Arrays.asList(KoralFrame.IS_AROUND));
+        koralGroup.setFrames(Collections.singletonList(KoralFrame.IS_AROUND));
 
         List<KoralObject> operands = new ArrayList<KoralObject>();
         operands.add(parseQueryNode(queryNode.getWithin()));
diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/AnnisQueryProcessor.java b/src/main/java/de/ids_mannheim/korap/query/serialize/AnnisQueryProcessor.java
index 5689705..4ccf2a6 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/AnnisQueryProcessor.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/AnnisQueryProcessor.java
@@ -995,7 +995,6 @@
     }
 
 
-    @SuppressWarnings("unchecked")
     private Map<String, Object> parseOperatorNode (ParseTree operatorNode) {
         Map<String, Object> relation = null;
         String operator = getNodeCat(operatorNode);
@@ -1131,7 +1130,6 @@
     }
 
 
-    @SuppressWarnings("unchecked")
     private Map<String, Object> parseEdgeSpec (ParseTree edgeSpec) {
         List<ParseTree> annos = getChildrenWithCat(edgeSpec, "edgeAnno");
         if (annos.size() != 1) {
diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/Cosmas2QueryProcessor.java b/src/main/java/de/ids_mannheim/korap/query/serialize/Cosmas2QueryProcessor.java
index 1ce1635..69a6293 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/Cosmas2QueryProcessor.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/Cosmas2QueryProcessor.java
@@ -1550,14 +1550,13 @@
                     Pattern.compile("([+\\-])?(sa|se|pa|pe|ta|te)");
             Matcher conditionMatcher =
                     conditionPattern.matcher(conditionsString);
-            String replacement = "#BED(" + m.group(1) + " , ";
+            StringBuilder replacement = new StringBuilder("#BED(" + m.group(1) + " , ");
             while (conditionMatcher.find()) {
-                replacement = replacement + conditionMatcher.group() + ",";
+                replacement.append(conditionMatcher.group()).append(",");
             }
             // remove trailing comma and close parenthesis
-            replacement =
-                    replacement.substring(0, replacement.length() - 1) + ")";
-            rewrittenQuery = rewrittenQuery.replace(match, replacement);
+            replacement = new StringBuilder(replacement.substring(0, replacement.length() - 1) + ")");
+            rewrittenQuery = rewrittenQuery.replace(match, replacement.toString());
         }
         return rewrittenQuery;
     }
diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/PoliqarpPlusQueryProcessor.java b/src/main/java/de/ids_mannheim/korap/query/serialize/PoliqarpPlusQueryProcessor.java
index aed8c3d..7cde9c1 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/PoliqarpPlusQueryProcessor.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/PoliqarpPlusQueryProcessor.java
@@ -639,9 +639,7 @@
         CollectionQueryProcessor cq = new CollectionQueryProcessor(
                 node.getChild(1).getText());
         requestMap.put("collection", cq.getRequestMap().get("collection"));
-        for (ParseTree child : getChildren(node)) {
-            visited.add(child);
-        }
+        visited.addAll(getChildren(node));
     }
 
 
diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/QueryUtils.java b/src/main/java/de/ids_mannheim/korap/query/serialize/QueryUtils.java
index 84932e8..0bfdc73 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/QueryUtils.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/QueryUtils.java
@@ -73,87 +73,86 @@
                 break;
         }
 
-        StringBuffer buffer = new StringBuffer();
-        buffer.append("<query><cypher><![CDATA[");
-        buffer.append(cypher);
-        buffer.append("]]></cypher>");
-        buffer.append("<wordAliasPrefix>wtok_</wordAliasPrefix>");
-        buffer.append("<contextColumn>sent</contextColumn>");
-        buffer.append("<contextIdColumn>sid</contextIdColumn>");
-        buffer.append("<textColumn>txt</textColumn>");
-        buffer.append("<startIndex>");
-        buffer.append(page);
-        buffer.append("</startIndex>");
-        buffer.append("<itemsPerPage>");
-        buffer.append(limit);
-        buffer.append("</itemsPerPage>");
-        buffer.append("<context>");
-        buffer.append("<left>");
-        buffer.append("<" + sctypel + ">");
-        buffer.append(cl);
-        buffer.append("</" + sctypel + ">");
-        buffer.append("</left>");
-        buffer.append("<right>");
-        buffer.append("<" + sctyper + ">");
-        buffer.append(cr);
-        buffer.append("</" + sctyper + ">");
-        buffer.append("</right>");
-        buffer.append("</context>");
-        buffer.append("</query>");
-        return buffer.toString();
+        return new StringBuffer()
+                .append("<query><cypher><![CDATA[")
+                .append(cypher)
+                .append("]]></cypher>")
+                .append("<wordAliasPrefix>wtok_</wordAliasPrefix>")
+                .append("<contextColumn>sent</contextColumn>")
+                .append("<contextIdColumn>sid</contextIdColumn>")
+                .append("<textColumn>txt</textColumn>")
+                .append("<startIndex>")
+                .append(page)
+                .append("</startIndex>")
+                .append("<itemsPerPage>")
+                .append(limit)
+                .append("</itemsPerPage>")
+                .append("<context>")
+                .append("<left>")
+                .append("<").append(sctypel).append(">")
+                .append(cl)
+                .append("</").append(sctypel).append(">")
+                .append("</left>")
+                .append("<right>")
+                .append("<").append(sctyper).append(">")
+                .append(cr)
+                .append("</").append(sctyper).append(">")
+                .append("</right>")
+                .append("</context>")
+                .append("</query>")
+                .toString();
     }
 
 
     public static String buildDotQuery (long sid, String graphdb_id) {
-        StringBuffer b = new StringBuffer();
-        b.append("<query>");
-        b.append("<sentenceId>");
-        b.append(sid);
-        b.append("</sentenceId>");
-        b.append("<gdbId>");
-        b.append(graphdb_id);
-        b.append("</gdbId>");
-        b.append("<hls>");
-        b.append("<hl>");
-        b.append(40857);
-        b.append("</hl>");
-        b.append("<hl>");
-        b.append(40856);
-        b.append("</hl>");
-        b.append("</hls>");
-        b.append("</query>");
-
-        return b.toString();
+        return new StringBuffer()
+                .append("<query>")
+                .append("<sentenceId>")
+                .append(sid)
+                .append("</sentenceId>")
+                .append("<gdbId>")
+                .append(graphdb_id)
+                .append("</gdbId>")
+                .append("<hls>")
+                .append("<hl>")
+                .append(40857)
+                .append("</hl>")
+                .append("<hl>")
+                .append(40856)
+                .append("</hl>")
+                .append("</hls>")
+                .append("</query>")
+                .toString();
     }
 
 
     public String buildaggreQuery (String query) {
-        StringBuffer b = new StringBuffer();
-        b.append("<query><cypher><![CDATA[");
-        b.append(query);
-        b.append("]]></cypher>");
-        b.append("<columns>");
-        b.append("<column agg='true' sum='false'>");
-        b.append("<cypherAlias>");
-        b.append("aggBy");
-        b.append("</cypherAlias>");
-        b.append("<displayName>");
-        b.append("Aggregate");
-        b.append("</displayName>");
-        b.append("</column>");
+        return new StringBuffer()
+                .append("<query><cypher><![CDATA[")
+                .append(query)
+                .append("]]></cypher>")
+                .append("<columns>")
+                .append("<column agg='true' sum='false'>")
+                .append("<cypherAlias>")
+                .append("aggBy")
+                .append("</cypherAlias>")
+                .append("<displayName>")
+                .append("Aggregate")
+                .append("</displayName>")
+                .append("</column>")
 
-        b.append("<column agg='fals' sum='true'>");
-        b.append("<cypherAlias>");
-        b.append("cnt");
-        b.append("</cypherAlias>");
-        b.append("<displayName>");
-        b.append("Count");
-        b.append("</displayName>");
-        b.append("</column>");
-        b.append("</columns>");
+                .append("<column agg='fals' sum='true'>")
+                .append("<cypherAlias>")
+                .append("cnt")
+                .append("</cypherAlias>")
+                .append("<displayName>")
+                .append("Count")
+                .append("</displayName>")
+                .append("</column>")
+                .append("</columns>")
 
-        b.append("</query>");
-        return b.toString();
+                .append("</query>")
+                .toString();
     }
 
 
diff --git a/src/test/java/de/ids_mannheim/korap/query/test/EmptyResultsTest.java b/src/test/java/de/ids_mannheim/korap/query/test/EmptyResultsTest.java
index a1a202f..eb0c9ec 100644
--- a/src/test/java/de/ids_mannheim/korap/query/test/EmptyResultsTest.java
+++ b/src/test/java/de/ids_mannheim/korap/query/test/EmptyResultsTest.java
@@ -10,8 +10,7 @@
 import java.util.List;
 import java.util.ArrayList;
 
-
-import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.*;
 
 /**
  * @author hanl
@@ -27,8 +26,8 @@
         QuerySerializer s = new QuerySerializer();
         s.setQuery("prox/unit=word/distance<=5", "cql");
         JsonNode node = mapper.valueToTree(s.build());
-        assertEquals(node.has("query"), false);
-        assertEquals(node.has("collection"), false);
+        assertFalse(node.has("query"));
+        assertFalse(node.has("collection"));
     }
 
 
@@ -38,8 +37,8 @@
         s.setQuery("[base=Wort]", "poliqarp");
 
         JsonNode node = mapper.valueToTree(s.build());
-        assertEquals(node.has("query"), true);
-        assertEquals(node.has("collection"), false);
+        assertTrue(node.has("query"));
+        assertFalse(node.has("collection"));
     }
 
 
@@ -49,7 +48,7 @@
         s.setQuery("[base=Wort]", "poliqarp");
 
         JsonNode node = mapper.valueToTree(s.build());
-        assertEquals(node.has("meta"), false);
+        assertFalse(node.has("meta"));
     }
 
     @Test
@@ -62,12 +61,12 @@
         s.addWarning(16, "Beispiel 2", null);
 
         JsonNode node = mapper.valueToTree(s.build());
-        assertEquals(true, node.has("warnings"));
+        assertTrue(node.has("warnings"));
         assertEquals(14, node.at("/warnings/0/0").asInt());
         assertEquals("Beispiel", node.at("/warnings/0/1").asText());
         assertEquals("Hui", node.at("/warnings/0/2").asText());
         assertEquals(16, node.at("/warnings/1/0").asInt());
         assertEquals("Beispiel 2", node.at("/warnings/1/1").asText());
-        assertEquals(false, node.has("/warnings/1/2"));
+        assertFalse(node.has("/warnings/1/2"));
     }    
 }
diff --git a/src/test/java/de/ids_mannheim/korap/query/test/annis/AnnisQueryProcessorTest.java b/src/test/java/de/ids_mannheim/korap/query/test/annis/AnnisQueryProcessorTest.java
index 58a1ea5..12da8b6 100644
--- a/src/test/java/de/ids_mannheim/korap/query/test/annis/AnnisQueryProcessorTest.java
+++ b/src/test/java/de/ids_mannheim/korap/query/test/annis/AnnisQueryProcessorTest.java
@@ -1,7 +1,5 @@
 package de.ids_mannheim.korap.query.test.annis;
 
-import static org.junit.Assert.assertEquals;
-
 import java.io.IOException;
 
 import org.junit.Test;
@@ -13,6 +11,8 @@
 import de.ids_mannheim.korap.query.serialize.QuerySerializer;
 import de.ids_mannheim.korap.query.serialize.util.StatusCodes;
 
+import static org.junit.Assert.*;
+
 /**
  * Tests for JSON-LD serialization of ANNIS QL queries.
  * 
@@ -214,8 +214,8 @@
         assertEquals("operation:sequence", res.at("/query/operation").asText());
         assertEquals("der", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("die", res.at("/query/operands/1/wrap/key").asText());
-        assertEquals(true, res.at("/query/inOrder").asBoolean());
-        assertEquals(true, res.at("/query/operands/2").isMissingNode());
+        assertTrue(res.at("/query/inOrder").asBoolean());
+        assertTrue(res.at("/query/operands/2").isMissingNode());
 
         query = "tok=\"der\" & tok=\"die\" & #1 .2,3 #2";
         qs.setQuery(query, "annis");
@@ -224,8 +224,8 @@
         assertEquals("operation:sequence", res.at("/query/operation").asText());
         assertEquals("der", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("die", res.at("/query/operands/1/wrap/key").asText());
-        assertEquals(true, res.at("/query/inOrder").asBoolean());
-        assertEquals(true, res.at("/query/operands/2").isMissingNode());
+        assertTrue(res.at("/query/inOrder").asBoolean());
+        assertTrue(res.at("/query/operands/2").isMissingNode());
         assertEquals("koral:distance", res.at("/query/distances/0/@type")
                 .asText());
         assertEquals("koral:boundary",
@@ -240,14 +240,14 @@
         assertEquals("operation:sequence", res.at("/query/operation").asText());
         assertEquals("der", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("die", res.at("/query/operands/1/wrap/key").asText());
-        assertEquals(true, res.at("/query/inOrder").asBoolean());
-        assertEquals(true, res.at("/query/operands/2").isMissingNode());
+        assertTrue(res.at("/query/inOrder").asBoolean());
+        assertTrue(res.at("/query/operands/2").isMissingNode());
         assertEquals("koral:distance", res.at("/query/distances/0/@type")
                 .asText());
         assertEquals("koral:boundary",
                 res.at("/query/distances/0/boundary/@type").asText());
         assertEquals(1, res.at("/query/distances/0/boundary/min").asInt());
-        assertEquals(true, res.at("/query/distances/0/boundary/max")
+        assertTrue(res.at("/query/distances/0/boundary/max")
                 .isMissingNode());
 
         query = "tok=\"der\" & tok=\"die\" & #1 .* #2";
@@ -256,7 +256,7 @@
         assertEquals("koral:boundary",
                 res.at("/query/distances/0/boundary/@type").asText());
         assertEquals(0, res.at("/query/distances/0/boundary/min").asInt());
-        assertEquals(true, res.at("/query/distances/0/boundary/max")
+        assertTrue(res.at("/query/distances/0/boundary/max")
                 .isMissingNode());
     }
 
@@ -270,8 +270,8 @@
         assertEquals("operation:sequence", res.at("/query/operation").asText());
         assertEquals("der", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("die", res.at("/query/operands/1/wrap/key").asText());
-        assertEquals(false, res.at("/query/inOrder").asBoolean());
-        assertEquals(true, res.at("/query/operands/2").isMissingNode());
+        assertFalse(res.at("/query/inOrder").asBoolean());
+        assertTrue(res.at("/query/operands/2").isMissingNode());
 
         query = "tok=\"der\" & tok=\"die\" & #1 ^2,3 #2";
         qs.setQuery(query, "annis");
@@ -280,8 +280,8 @@
         assertEquals("operation:sequence", res.at("/query/operation").asText());
         assertEquals("der", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("die", res.at("/query/operands/1/wrap/key").asText());
-        assertEquals(false, res.at("/query/inOrder").asBoolean());
-        assertEquals(true, res.at("/query/operands/2").isMissingNode());
+        assertFalse(res.at("/query/inOrder").asBoolean());
+        assertTrue(res.at("/query/operands/2").isMissingNode());
         assertEquals("koral:distance", res.at("/query/distances/0/@type")
                 .asText());
         assertEquals("koral:boundary",
@@ -295,9 +295,9 @@
         assertEquals("koral:boundary",
                 res.at("/query/distances/0/boundary/@type").asText());
         assertEquals(0, res.at("/query/distances/0/boundary/min").asInt());
-        assertEquals(true, res.at("/query/distances/0/boundary/max")
+        assertTrue(res.at("/query/distances/0/boundary/max")
                 .isMissingNode());
-        assertEquals(false, res.at("/query/inOrder").asBoolean());
+        assertFalse(res.at("/query/inOrder").asBoolean());
     }
 
 
@@ -485,7 +485,7 @@
         // the resulting query should be equivalent to PQ+:  focus(2:dominates(focus(1:{1:<A>}<B>),{2:<C>}))<D> 
         qs.setQuery(query, "annis");
         res = mapper.readTree(qs.toJSON());
-        assertEquals(true, res.at("/query/@type").isMissingNode());
+        assertTrue(res.at("/query/@type").isMissingNode());
         assertEquals(StatusCodes.UNBOUND_ANNIS_RELATION, res.at("/errors/0/0")
                 .asInt());
     }
@@ -930,7 +930,7 @@
         assertEquals("operation:focus", res.at("/query/operands/1/operation")
                 .asText());
         assertEquals(131, res.at("/query/operands/1/classRef/0").asInt());
-        assertEquals(true, res.at("/query/operands/1/operands").isMissingNode());
+        assertTrue(res.at("/query/operands/1/operands").isMissingNode());
     }
 
 
@@ -975,7 +975,7 @@
         assertEquals("NP", res.at("/query/wrap/key").asText());
         assertEquals("match:eq", res.at("/query/wrap/match").asText());
         assertEquals("koral:term", res.at("/query/attr/@type").asText());
-        assertEquals(true, res.at("/query/attr/root").asBoolean());
+        assertTrue(res.at("/query/attr/root").asBoolean());
 
         query = "cnx/cat=\"NP\" & #1:root & #1:arity=2";
         qs.setQuery(query, "annis");
@@ -987,7 +987,7 @@
         assertEquals("koral:termGroup", res.at("/query/attr/@type").asText());
         assertEquals("koral:term", res.at("/query/attr/operands/0/@type")
                 .asText());
-        assertEquals(true, res.at("/query/attr/operands/0/root").asBoolean());
+        assertTrue(res.at("/query/attr/operands/0/root").asBoolean());
         assertEquals("koral:term", res.at("/query/attr/operands/1/@type")
                 .asText());
         assertEquals("koral:boundary",
@@ -1044,10 +1044,8 @@
                 "koral:span",
                 res.at("/query/operands/0/operands/0/operands/0/operands/0/@type")
                         .asText());
-        assertEquals(
-                true,
-                res.at("/query/operands/0/operands/0/operands/0/operands/0/key")
-                        .isMissingNode());
+        assertTrue(res.at("/query/operands/0/operands/0/operands/0/operands/0/key")
+                .isMissingNode());
         assertEquals("koral:span",
                 res.at("/query/operands/0/operands/0/operands/1/@type")
                         .asText());
diff --git a/src/test/java/de/ids_mannheim/korap/query/test/collection/CollectionQueryProcessorTest.java b/src/test/java/de/ids_mannheim/korap/query/test/collection/CollectionQueryProcessorTest.java
index 5829482..8f371de 100644
--- a/src/test/java/de/ids_mannheim/korap/query/test/collection/CollectionQueryProcessorTest.java
+++ b/src/test/java/de/ids_mannheim/korap/query/test/collection/CollectionQueryProcessorTest.java
@@ -1,9 +1,5 @@
 package de.ids_mannheim.korap.query.test.collection;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertFalse;
-import static org.junit.Assert.assertTrue;
-
 import java.io.IOException;
 
 import org.junit.Test;
@@ -16,6 +12,8 @@
 import de.ids_mannheim.korap.query.serialize.QuerySerializer;
 import de.ids_mannheim.korap.query.serialize.QueryUtils;
 
+import static org.junit.Assert.*;
+
 public class CollectionQueryProcessorTest {
 
     private String query = "foo";
@@ -105,7 +103,7 @@
         assertEquals("koral:doc", res.at("/collection/@type").asText());
         assertEquals("textClass", res.at("/collection/key").asText());
         assertEquals("politik", res.at("/collection/value").asText());
-        assertFalse(res.at("/collection/type").asText().equals("type:regex"));
+        assertNotEquals("type:regex", res.at("/collection/type").asText());
         assertEquals("match:eq", res.at("/collection/match").asText());
 
         collection = "textClass!=politik";
@@ -115,7 +113,7 @@
         assertEquals("koral:doc", res.at("/collection/@type").asText());
         assertEquals("textClass", res.at("/collection/key").asText());
         assertEquals("politik", res.at("/collection/value").asText());
-        assertFalse(res.at("/collection/type").asText().equals("type:regex"));
+        assertNotEquals("type:regex", res.at("/collection/type").asText());
         assertEquals("match:ne", res.at("/collection/match").asText());
     }
 
@@ -348,7 +346,7 @@
                 .asText());
         assertEquals("pubDate", res.at("/collection/operands/1/key").asText());
         assertEquals("2014", res.at("/collection/operands/1/value").asText());
-        assertEquals(true, res.at("/collection/operands/1/type")
+        assertTrue(res.at("/collection/operands/1/type")
                 .isMissingNode());
         assertEquals("match:eq", res.at("/collection/operands/1/match")
                 .asText());
@@ -658,7 +656,7 @@
         assertEquals("koral:doc", res.at("/collection/@type").asText());
         assertEquals("pubDate", res.at("/collection/key").asText());
         assertEquals("2000", res.at("/collection/value").asText());
-        assertEquals(true, res.at("/collection/type").isMissingNode());
+        assertTrue(res.at("/collection/type").isMissingNode());
         assertEquals("match:eq", res.at("/collection/match").asText());
 
         collection = "pubDate since 2000";
@@ -702,7 +700,7 @@
         assertEquals("koral:doc", res.at("/collection/@type").asText());
         assertEquals("pubDate", res.at("/collection/key").asText());
         assertEquals("2000-12", res.at("/collection/value").asText());
-        assertEquals(true, res.at("/collection/type").isMissingNode());
+        assertTrue(res.at("/collection/type").isMissingNode());
         assertEquals("match:eq", res.at("/collection/match").asText());
 
         collection = "pubDate since 2000-02-01";
@@ -759,11 +757,11 @@
         String date_1 = "2015-05";
         String date_2 = "2015-05-13";
         String date_3 = "2015-23-01";
-        assertEquals(false, QueryUtils.checkDateValidity(fake_date));
-        assertEquals(false, QueryUtils.checkDateValidity(fake_date_2));
-        assertEquals(true, QueryUtils.checkDateValidity(date));
-        assertEquals(true, QueryUtils.checkDateValidity(date_1));
-        assertEquals(true, QueryUtils.checkDateValidity(date_2));
-        assertEquals(false, QueryUtils.checkDateValidity(date_3));
+        assertFalse(QueryUtils.checkDateValidity(fake_date));
+        assertFalse(QueryUtils.checkDateValidity(fake_date_2));
+        assertTrue(QueryUtils.checkDateValidity(date));
+        assertTrue(QueryUtils.checkDateValidity(date_1));
+        assertTrue(QueryUtils.checkDateValidity(date_2));
+        assertFalse(QueryUtils.checkDateValidity(date_3));
     }
 }
diff --git a/src/test/java/de/ids_mannheim/korap/query/test/fcsql/FCSQLQueryProcessorTest.java b/src/test/java/de/ids_mannheim/korap/query/test/fcsql/FCSQLQueryProcessorTest.java
index 01881ee..7ca180d 100644
--- a/src/test/java/de/ids_mannheim/korap/query/test/fcsql/FCSQLQueryProcessorTest.java
+++ b/src/test/java/de/ids_mannheim/korap/query/test/fcsql/FCSQLQueryProcessorTest.java
@@ -1,6 +1,7 @@
 package de.ids_mannheim.korap.query.test.fcsql;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 
 import java.io.IOException;
 import java.util.List;
@@ -106,7 +107,7 @@
         error = FCSQLQueryProcessorTest.getError(new FCSQLQueryProcessor(query));
         assertEquals(306, error.get(0));
         String msg = (String) error.get(1);
-        assertEquals(true, msg.startsWith("Regexflags"));
+        assertTrue(msg.startsWith("Regexflags"));
 
         query = "\"Fliegen\" /d";
         error = FCSQLQueryProcessorTest.getError(new FCSQLQueryProcessor(query));
diff --git a/src/test/java/de/ids_mannheim/korap/query/test/poliqarpplus/EmptyTokenTest.java b/src/test/java/de/ids_mannheim/korap/query/test/poliqarpplus/EmptyTokenTest.java
index 6c215f9..a689a14 100644
--- a/src/test/java/de/ids_mannheim/korap/query/test/poliqarpplus/EmptyTokenTest.java
+++ b/src/test/java/de/ids_mannheim/korap/query/test/poliqarpplus/EmptyTokenTest.java
@@ -39,7 +39,7 @@
         qs.setQuery(query, "poliqarpplus");
         res = mapper.readTree(qs.toJSON());
         assertEquals("koral:token", res.at("/query/@type").asText());
-        assertEquals(true, res.at("/query/key").isMissingNode());
+        assertTrue(res.at("/query/key").isMissingNode());
     }
 
     @Test
@@ -107,7 +107,7 @@
         res = mapper.readTree(qs.toJSON());
         operands = Lists.newArrayList(res.at("/query/operands").elements());
         assertEquals("koral:token", operands.get(0).at("/@type").asText());
-        assertEquals(true, operands.get(0).at("/key").isMissingNode());
+        assertTrue(operands.get(0).at("/key").isMissingNode());
         assertEquals("koral:token", operands.get(1).at("/@type").asText());
         assertEquals("Mann", operands.get(1).at("/wrap/key").asText());
 
@@ -124,7 +124,7 @@
         operands = Lists
                 .newArrayList(operands.get(0).at("/operands").elements());
         assertEquals("koral:token", operands.get(0).at("/@type").asText());
-        assertEquals(true, operands.get(0).at("/key").isMissingNode());
+        assertTrue(operands.get(0).at("/key").isMissingNode());
     }
 
 
@@ -141,8 +141,7 @@
         assertEquals(2, operands.get(0).at("/boundary/max").asInt());
         assertEquals("koral:token",
                 operands.get(0).at("/operands/0/@type").asText());
-        assertEquals(true,
-                operands.get(0).at("/operands/0/key").isMissingNode());
+        assertTrue(operands.get(0).at("/operands/0/key").isMissingNode());
         assertEquals("koral:token", operands.get(1).at("/@type").asText());
         assertEquals("bose", operands.get(1).at("/wrap/key").asText());
         assertEquals("koral:token", operands.get(2).at("/@type").asText());
@@ -157,7 +156,7 @@
         res = mapper.readTree(qs.toJSON());
         operands = Lists.newArrayList(res.at("/query/operands").elements());
         assertEquals("koral:token", operands.get(1).at("/@type").asText());
-        assertEquals(true, operands.get(1).at("/key").isMissingNode());
+        assertTrue(operands.get(1).at("/key").isMissingNode());
 
         query = "[base=Mann][]{3}";
         qs.setQuery(query, "poliqarpplus");
@@ -165,7 +164,7 @@
         operands = Lists.newArrayList(res.at("/query/operands").elements());
         res = operands.get(1);
         assertEquals("koral:group", res.at("/@type").asText());
-        assertEquals(true, res.at("/wrap/key").isMissingNode());
+        assertTrue(res.at("/wrap/key").isMissingNode());
         assertEquals("operation:repetition", res.at("/operation").asText());
         assertEquals(3, res.at("/boundary/min").asInt());
         assertEquals(3, res.at("/boundary/max").asInt());
@@ -199,7 +198,7 @@
         assertEquals("lemma", operands.get(0).at("/wrap/layer").asText());
         assertEquals("match:eq", operands.get(0).at("/wrap/match").asText());
         assertEquals("koral:token", operands.get(1).at("/@type").asText());
-        assertEquals(true, operands.get(1).at("/wrap/key").isMissingNode());
+        assertTrue(operands.get(1).at("/wrap/key").isMissingNode());
         assertEquals("koral:token", operands.get(2).at("/@type").asText());
         assertEquals("Mann", operands.get(2).at("/wrap/key").asText());
         assertEquals("lemma", operands.get(2).at("/wrap/layer").asText());
@@ -228,7 +227,7 @@
                 .newArrayList(operands.get(1).at("/operands").elements());
         assertEquals(1, operands.size());
         assertEquals("koral:token", operands.get(0).at("/@type").asText());
-        assertEquals(true, operands.get(0).at("/wrap/key").isMissingNode());
+        assertTrue(operands.get(0).at("/wrap/key").isMissingNode());
 
     }
 
@@ -244,7 +243,7 @@
         assertEquals(3, operands.size());
         
         assertEquals("koral:token", operands.get(1).at("/@type").asText());
-        assertEquals(true, operands.get(1).at("/wrap/key").isMissingNode());
+        assertTrue(operands.get(1).at("/wrap/key").isMissingNode());
         
         assertEquals("koral:group", operands.get(2).at("/@type").asText());
         assertEquals("operation:repetition",
@@ -277,7 +276,7 @@
         assertEquals(1, operands.get(0).at("/boundary/max").asInt());
         
         assertEquals("koral:token", operands.get(1).at("/@type").asText());
-        assertEquals(true, operands.get(1).at("/wrap/key").isMissingNode());
+        assertTrue(operands.get(1).at("/wrap/key").isMissingNode());
         
         assertEquals("koral:group", operands.get(2).at("/@type").asText());
         assertEquals("operation:repetition",
@@ -310,7 +309,7 @@
                 .newArrayList(operands.get(1).at("/operands").elements());
         assertEquals(1, operands.size());
         assertEquals("koral:token", operands.get(0).at("/@type").asText());
-        assertEquals(true, operands.get(0).at("/wrap/key").isMissingNode());
+        assertTrue(operands.get(0).at("/wrap/key").isMissingNode());
     }
 
 
@@ -330,12 +329,12 @@
         assertEquals("koral:boundary",
                 operands.get(1).at("/boundary/@type").asText());
         assertEquals(1, operands.get(1).at("/boundary/min").asInt());
-        assertEquals(true, operands.get(1).at("/boundary/max").isMissingNode());
+        assertTrue(operands.get(1).at("/boundary/max").isMissingNode());
         operands = Lists
                 .newArrayList(operands.get(1).at("/operands").elements());
         assertEquals(1, operands.size());
         assertEquals("koral:token", operands.get(0).at("/@type").asText());
-        assertEquals(true, operands.get(0).at("/wrap/key").isMissingNode());
+        assertTrue(operands.get(0).at("/wrap/key").isMissingNode());
     }
 
 
@@ -356,12 +355,12 @@
         assertEquals("koral:boundary",
                 operands.get(1).at("/boundary/@type").asText());
         assertEquals(0, operands.get(1).at("/boundary/min").asInt());
-        assertEquals(true, operands.get(1).at("/boundary/max").isMissingNode());
+        assertTrue(operands.get(1).at("/boundary/max").isMissingNode());
         operands = Lists
                 .newArrayList(operands.get(1).at("/operands").elements());
         assertEquals(1, operands.size());
         assertEquals("koral:token", operands.get(0).at("/@type").asText());
-        assertEquals(true, operands.get(0).at("/wrap/key").isMissingNode());
+        assertTrue(operands.get(0).at("/wrap/key").isMissingNode());
     }
 
 
@@ -387,8 +386,7 @@
         assertEquals(5, operands.get(1).at("/boundary/max").asInt());
         assertEquals("koral:token",
                 operands.get(1).at("/operands/0/@type").asText());
-        assertEquals(true,
-                operands.get(1).at("/operands/0/wrap/key").isMissingNode());
+        assertTrue(operands.get(1).at("/operands/0/wrap/key").isMissingNode());
 
         assertEquals("koral:token", operands.get(2).at("/@type").asText());
         assertEquals("Mann", operands.get(2).at("/wrap/key").asText());
@@ -402,8 +400,7 @@
         assertEquals(2, operands.get(3).at("/boundary/max").asInt());
         assertEquals("koral:token",
                 operands.get(3).at("/operands/0/@type").asText());
-        assertEquals(true,
-                operands.get(3).at("/operands/0/wrap/key").isMissingNode());
+        assertTrue(operands.get(3).at("/operands/0/wrap/key").isMissingNode());
 
         assertEquals("koral:token", operands.get(4).at("/@type").asText());
         assertEquals("Frau", operands.get(4).at("/wrap/key").asText());
@@ -419,8 +416,8 @@
 
         assertEquals("koral:group", res.at("/query/@type").asText());
         assertEquals("operation:sequence", res.at("/query/operation").asText());
-        assertEquals(true, res.at("/query/inOrder").isMissingNode());
-        assertEquals(true, res.at("/query/distances").isMissingNode());
+        assertTrue(res.at("/query/inOrder").isMissingNode());
+        assertTrue(res.at("/query/distances").isMissingNode());
 
         operands = Lists.newArrayList(res.at("/query/operands").elements());
         assertEquals(4, operands.size());
@@ -443,7 +440,7 @@
         assertEquals("koral:boundary",
                 operands.get(2).at("/boundary/@type").asText());
         assertEquals(0, operands.get(2).at("/boundary/min").asInt());
-        assertEquals(true, operands.get(2).at("/boundary/max").isMissingNode());
+        assertTrue(operands.get(2).at("/boundary/max").isMissingNode());
 
         assertEquals("koral:group", operands.get(3).at("/@type").asText());
         assertEquals("operation:position",
@@ -466,11 +463,11 @@
         assertEquals("koral:group", res.at("/query/@type").asText());
         assertEquals("operation:position", res.at("/query/operation").asText());
         assertEquals("frames:isAround", res.at("/query/frames/0").asText());
-        assertEquals(true, res.at("/query/frames/1").isMissingNode());
+        assertTrue(res.at("/query/frames/1").isMissingNode());
         assertEquals("koral:span", res.at("/query/operands/0/@type").asText());
         assertEquals("s", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("koral:token", res.at("/query/operands/1/@type").asText());
-        assertEquals(true, res.at("/query/operands/1/key").isMissingNode());
+        assertTrue(res.at("/query/operands/1/key").isMissingNode());
 
         query = "contains(<s>, []{3})";
         qs.setQuery(query, "poliqarpplus");
@@ -481,8 +478,7 @@
                 res.at("/query/operands/1/operation").asText());
         assertEquals("koral:token",
                 res.at("/query/operands/1/operands/0/@type").asText());
-        assertEquals(true,
-                res.at("/query/operands/1/operands/0/key").isMissingNode());
+        assertTrue(res.at("/query/operands/1/operands/0/key").isMissingNode());
 
         query = "contains(<s>, {1:[]{3}})";
         qs.setQuery(query, "poliqarpplus");
@@ -495,7 +491,7 @@
                 res.at("/query/operands/1/operands/0/operation").asText());
         assertEquals("koral:token", res
                 .at("/query/operands/1/operands/0/operands/0/@type").asText());
-        assertEquals(true, res.at("/query/operands/1/operands/0/operands/0/key")
+        assertTrue(res.at("/query/operands/1/operands/0/operands/0/key")
                 .isMissingNode());
 
         query = "startswith(<s>, [][base=Mann])";
@@ -507,7 +503,7 @@
         operands = Lists.newArrayList(res.at("/query/operands"));
         operands = Lists.newArrayList(operands.get(1).at("/operands"));
         assertEquals("koral:token", operands.get(0).at("/@type").asText());
-        assertEquals(true, operands.get(0).at("/key").isMissingNode());
+        assertTrue(operands.get(0).at("/key").isMissingNode());
     }
 
     @Test
@@ -517,8 +513,8 @@
         res = mapper.readTree(qs.toJSON());
         assertEquals("koral:group", res.at("/query/@type").asText());
         assertEquals("operation:sequence", res.at("/query/operation").asText());
-        assertEquals(true, res.at("/query/inOrder").isMissingNode());
-        assertEquals(true, res.at("/query/distances").isMissingNode());
+        assertTrue(res.at("/query/inOrder").isMissingNode());
+        assertTrue(res.at("/query/distances").isMissingNode());
         operands = Lists.newArrayList(res.at("/query/operands").elements());
         assertEquals("der", operands.get(0).at("/wrap/key").asText());
         assertEquals("Mann", operands.get(2).at("/wrap/key").asText());
@@ -529,7 +525,7 @@
         operands = Lists
                 .newArrayList(operands.get(1).at("/operands").elements());
         assertEquals("koral:token", operands.get(0).at("/@type").asText());
-        assertEquals(true, operands.get(0).at("/wrap").isMissingNode());
+        assertTrue(operands.get(0).at("/wrap").isMissingNode());
         assertEquals(1, res.at("/meta/highlight/0").asInt());
     }
 
diff --git a/src/test/java/de/ids_mannheim/korap/query/test/poliqarpplus/PoliqarpPlusQueryProcessorTest.java b/src/test/java/de/ids_mannheim/korap/query/test/poliqarpplus/PoliqarpPlusQueryProcessorTest.java
index f8bfa1a..f1562a0 100644
--- a/src/test/java/de/ids_mannheim/korap/query/test/poliqarpplus/PoliqarpPlusQueryProcessorTest.java
+++ b/src/test/java/de/ids_mannheim/korap/query/test/poliqarpplus/PoliqarpPlusQueryProcessorTest.java
@@ -342,7 +342,7 @@
         assertEquals("koral:token", res.at("/query/@type").asText());
         assertEquals("koral:term", res.at("/query/wrap/@type").asText());
         assertEquals("deutscher", res.at("/query/wrap/key").asText());
-        assertEquals(true, res.at("/query/wrap/flags:caseInsensitive")
+        assertTrue(res.at("/query/wrap/flags:caseInsensitive")
                 .isMissingNode());
         assertEquals("flags:caseInsensitive", res.at("/query/wrap/flags/0")
                 .asText());
@@ -366,7 +366,7 @@
         assertEquals("koral:token", res.at("/query/@type").asText());
         assertEquals("koral:term", res.at("/query/wrap/@type").asText());
         assertEquals("deutscher", res.at("/query/wrap/key").asText());
-        assertEquals(true, res.at("/query/wrap/flags/0").isMissingNode());
+        assertTrue(res.at("/query/wrap/flags/0").isMissingNode());
         assertEquals("orth", res.at("/query/wrap/layer").asText());
         assertEquals("match:eq", res.at("/query/wrap/match").asText());
 
@@ -386,7 +386,7 @@
         assertEquals("Bundestag", operands.get(1).at("/wrap/key").asText());
         assertEquals("orth", operands.get(1).at("/wrap/layer").asText());
         assertEquals("match:eq", operands.get(1).at("/wrap/match").asText());
-        assertEquals(true, operands.get(1).at("/wrap/flags/0").isMissingNode());
+        assertTrue(operands.get(1).at("/wrap/flags/0").isMissingNode());
 
         query = "deutscher/i Bundestag";
         qs.setQuery(query, "poliqarpplus");
@@ -404,7 +404,7 @@
         assertEquals("Bundestag", operands.get(1).at("/wrap/key").asText());
         assertEquals("orth", operands.get(1).at("/wrap/layer").asText());
         assertEquals("match:eq", operands.get(1).at("/wrap/match").asText());
-        assertEquals(true, operands.get(1).at("/wrap/flags:caseInsensitive")
+        assertTrue(operands.get(1).at("/wrap/flags:caseInsensitive")
                 .isMissingNode());
     }
 
@@ -515,7 +515,7 @@
         qs.setQuery(query, "poliqarpplus");
         res = mapper.readTree(qs.toJSON());
         assertEquals(3, res.at("/query/boundary/min").asInt());
-        assertEquals(true, res.at("/query/boundary/max").isMissingNode());
+        assertTrue(res.at("/query/boundary/max").isMissingNode());
 
         query = "der{3,7}";
         qs.setQuery(query, "poliqarpplus");
@@ -527,13 +527,13 @@
         qs.setQuery(query, "poliqarpplus");
         res = mapper.readTree(qs.toJSON());
         assertEquals(0, res.at("/query/boundary/min").asInt());
-        assertEquals(true, res.at("/query/boundary/max").isMissingNode());
+        assertTrue(res.at("/query/boundary/max").isMissingNode());
 
         query = "der+";
         qs.setQuery(query, "poliqarpplus");
         res = mapper.readTree(qs.toJSON());
         assertEquals(1, res.at("/query/boundary/min").asInt());
-        assertEquals(true, res.at("/query/boundary/max").isMissingNode());
+        assertTrue(res.at("/query/boundary/max").isMissingNode());
     };
 
 
@@ -555,7 +555,7 @@
         qs.setQuery(query, "poliqarpplus");
         res = mapper.readTree(qs.toJSON());
         assertEquals(3, res.at("/query/operands/1/boundary/min").asInt());
-        assertEquals(true, res.at("/query/operands/1/boundary/max")
+        assertTrue(res.at("/query/operands/1/boundary/max")
                 .isMissingNode());
 
         query = "contains(<s>, (der){,3})";
@@ -574,7 +574,7 @@
         qs.setQuery(query, "poliqarpplus");
         res = mapper.readTree(qs.toJSON());
         assertEquals(0, res.at("/query/operands/1/boundary/min").asInt());
-        assertEquals(true, res.at("/query/operands/1/boundary/max")
+        assertTrue(res.at("/query/operands/1/boundary/max")
                 .isMissingNode());
     };
 
@@ -587,7 +587,7 @@
         assertEquals("koral:group", res.at("/query/@type").asText());
         assertEquals("operation:position", res.at("/query/operation").asText());
         assertEquals("frames:isAround", res.at("/query/frames/0").asText());
-        assertEquals(true, res.at("/query/frames/1").isMissingNode());
+        assertTrue(res.at("/query/frames/1").isMissingNode());
         assertEquals("koral:span", res.at("/query/operands/0/@type").asText());
         assertEquals("s", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("koral:token", res.at("/query/operands/1/@type").asText());
@@ -629,7 +629,7 @@
                 res.at("/query/operands/1/operands/1/operation").asText());
         assertEquals(0, res.at("/query/operands/1/operands/1/boundary/min")
                 .asInt());
-        assertEquals(true, res.at("/query/operands/1/operands/1/boundary/max")
+        assertTrue(res.at("/query/operands/1/operands/1/boundary/max")
                 .isMissingNode());
         assertEquals("Mann",
                 res.at("/query/operands/1/operands/1/operands/0/wrap/key")
@@ -1041,7 +1041,7 @@
         assertEquals("koral:group", res.at("/query/@type").asText());
         assertEquals("operation:class", res.at("/query/operation").asText());
         assertEquals(1, res.at("/query/classOut").asInt());
-        assertEquals(true, res.at("/query/classIn").isMissingNode());
+        assertTrue(res.at("/query/classIn").isMissingNode());
         assertEquals("Mann", res.at("/query/operands/0/wrap/key").asText());
 
         query = "{[base=Mann][orth=Frau]}";
@@ -1050,7 +1050,7 @@
         assertEquals("koral:group", res.at("/query/@type").asText());
         assertEquals("operation:class", res.at("/query/operation").asText());
         assertEquals(1, res.at("/query/classOut").asInt());
-        assertEquals(true, res.at("/query/classIn").isMissingNode());
+        assertTrue(res.at("/query/classIn").isMissingNode());
         assertEquals("Mann", res.at("/query/operands/0/operands/0/wrap/key")
                 .asText());
         assertEquals("Frau", res.at("/query/operands/0/operands/1/wrap/key")
@@ -1067,7 +1067,7 @@
         assertEquals("operation:class", res.at("/query/operands/1/operation")
                 .asText());
         assertEquals(1, res.at("/query/operands/1/classOut").asInt());
-        assertEquals(true, res.at("/query/classIn").isMissingNode());
+        assertTrue(res.at("/query/classIn").isMissingNode());
         assertEquals("Mann", res.at("/query/operands/0/operands/0/wrap/key")
                 .asText());
         assertEquals("Frau", res.at("/query/operands/1/operands/0/wrap/key")
@@ -1082,7 +1082,7 @@
         assertEquals("operation:class", res.at("/query/operands/1/operation")
                 .asText());
         assertEquals(1, res.at("/query/operands/1/classOut").asInt());
-        assertEquals(true, res.at("/query/operands/1/classIn").isMissingNode());
+        assertTrue(res.at("/query/operands/1/classIn").isMissingNode());
         assertEquals("Mann",
                 res.at("/query/operands/1/operands/0/operands/0/wrap/key")
                         .asText());
@@ -1099,7 +1099,7 @@
         assertEquals("operation:class", res.at("/query/operands/0/operation")
                 .asText());
         assertEquals(1, res.at("/query/operands/0/classOut").asInt());
-        assertEquals(true, res.at("/query/operands/0/classIn").isMissingNode());
+        assertTrue(res.at("/query/operands/0/classIn").isMissingNode());
         assertEquals("Mann",
                 res.at("/query/operands/0/operands/0/operands/0/wrap/key")
                         .asText());
@@ -1226,7 +1226,7 @@
         qs.setQuery(query, "poliqarpplus");
         res = mapper.readTree(qs.toJSON());
         assertEquals(3, res.at("/query/classRef/0").asInt());
-        assertEquals(true, res.at("/query/classRef/1").isMissingNode());
+        assertTrue(res.at("/query/classRef/1").isMissingNode());
         assertEquals("koral:reference", res.at("/query/@type").asText());
         assertEquals("operation:split", res.at("/query/operation").asText());
 
@@ -1260,7 +1260,7 @@
         assertEquals("koral:reference", res.at("/query/@type").asText());
         assertEquals("operation:focus", res.at("/query/operation").asText());
         assertEquals(1, res.at("/query/spanRef/0").asInt());
-        assertEquals(true, res.at("/query/spanRef/1").isMissingNode());
+        assertTrue(res.at("/query/spanRef/1").isMissingNode());
         assertEquals("s", res.at("/query/operands/0/wrap/key").asText());
 
         query = "submatch(1,4:<s>)";
@@ -1354,7 +1354,7 @@
         assertEquals("cnx", res.at("/query/relation/wrap/foundry").asText());
         assertEquals("c", res.at("/query/relation/wrap/layer").asText());
         assertEquals(0, res.at("/query/relation/boundary/min").asInt());
-        assertEquals(true, res.at("/query/relation/boundary/max")
+        assertTrue(res.at("/query/relation/boundary/max")
                 .isMissingNode());
 
         query = "dominates(cnx/c{1,5}:<vp>,<np>)";
@@ -1598,7 +1598,7 @@
         assertEquals("koral:group", res.at("/query/@type").asText());
         assertEquals("operation:position", res.at("/query/operation").asText());
         assertEquals("frames:isAround", res.at("/query/frames/0").asText());
-        assertEquals(true, res.at("/query/frames/1").isMissingNode());
+        assertTrue(res.at("/query/frames/1").isMissingNode());
         assertEquals("koral:span", res.at("/query/operands/0/@type").asText());
         assertEquals("s", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("koral:token", res.at("/query/operands/1/@type").asText());
@@ -1609,7 +1609,7 @@
         assertEquals("koral:group", res.at("/query/@type").asText());
         assertEquals("operation:position", res.at("/query/operation").asText());
         assertEquals("frames:isAround", res.at("/query/frames/0").asText());
-        assertEquals(true, res.at("/query/frames/1").isMissingNode());
+        assertTrue(res.at("/query/frames/1").isMissingNode());
         assertEquals("koral:span", res.at("/query/operands/0/@type").asText());
         assertEquals("s", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("koral:token", res.at("/query/operands/1/@type").asText());
diff --git a/src/test/java/de/ids_mannheim/korap/test/cosmas2/Cosmas2QueryProcessorTest.java b/src/test/java/de/ids_mannheim/korap/test/cosmas2/Cosmas2QueryProcessorTest.java
index 26aa5d7..0722c9b 100644
--- a/src/test/java/de/ids_mannheim/korap/test/cosmas2/Cosmas2QueryProcessorTest.java
+++ b/src/test/java/de/ids_mannheim/korap/test/cosmas2/Cosmas2QueryProcessorTest.java
@@ -1,8 +1,5 @@
 package de.ids_mannheim.korap.test.cosmas2;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertTrue;
-
 import java.io.IOException;
 import java.util.ArrayList;
 
@@ -15,6 +12,8 @@
 import de.ids_mannheim.korap.query.serialize.QuerySerializer;
 import de.ids_mannheim.korap.query.serialize.util.StatusCodes;
 
+import static org.junit.Assert.*;
+
 /**
  * Tests for JSON-LD serialization of Cosmas II queries.
  * 
@@ -205,7 +204,7 @@
         assertEquals("operation:sequence", res.at("/query/operation").asText());
         assertEquals("der", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("Mann", res.at("/query/operands/1/wrap/key").asText());
-        assertEquals(true, res.at("/query/operands/2").isMissingNode());
+        assertTrue(res.at("/query/operands/2").isMissingNode());
 
         query = "der Mann schläft";
         qs.setQuery(query, "cosmas2");
@@ -215,7 +214,7 @@
         assertEquals("der", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("Mann", res.at("/query/operands/1/wrap/key").asText());
         assertEquals("schläft", res.at("/query/operands/2/wrap/key").asText());
-        assertEquals(true, res.at("/query/operands/3").isMissingNode());
+        assertTrue(res.at("/query/operands/3").isMissingNode());
 
         query = "der Mann schläft lang";
         qs.setQuery(query, "cosmas2");
@@ -226,14 +225,14 @@
         assertEquals("Mann", res.at("/query/operands/1/wrap/key").asText());
         assertEquals("schläft", res.at("/query/operands/2/wrap/key").asText());
         assertEquals("lang", res.at("/query/operands/3/wrap/key").asText());
-        assertEquals(true, res.at("/query/operands/4").isMissingNode());
+        assertTrue(res.at("/query/operands/4").isMissingNode());
 
         query = "#ELEM(s)";
         qs.setQuery(query, "cosmas2");
         res = mapper.readTree(qs.toJSON());
         assertEquals("koral:span", res.at("/query/@type").asText());
         assertEquals("s", res.at("/query/wrap/key").asText());
-        assertEquals(true, res.at("/query/key").isMissingNode());
+        assertTrue(res.at("/query/key").isMissingNode());
 		
         query = "der #ELEM(W)";
         qs.setQuery(query, "cosmas2");
@@ -243,7 +242,7 @@
         assertEquals("der", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("w", res.at("/query/operands/1/wrap/key").asText());
         assertEquals("koral:span", res.at("/query/operands/1/@type").asText());
-        assertEquals(true, res.at("/query/operands/2").isMissingNode());
+        assertTrue(res.at("/query/operands/2").isMissingNode());
 
         query = "der #ELEM(W) Mann";
         qs.setQuery(query, "cosmas2");
@@ -254,7 +253,7 @@
         assertEquals("w", res.at("/query/operands/1/wrap/key").asText());
         assertEquals("koral:span", res.at("/query/operands/1/@type").asText());
         assertEquals("Mann", res.at("/query/operands/2/wrap/key").asText());
-        assertEquals(true, res.at("/query/operands/3").isMissingNode());
+        assertTrue(res.at("/query/operands/3").isMissingNode());
 
         query = "der MORPH(p=ADJA) Mann";
         qs.setQuery(query, "cosmas2");
@@ -265,7 +264,7 @@
         assertEquals("ADJA", res.at("/query/operands/1/wrap/key").asText());
         assertEquals("p", res.at("/query/operands/1/wrap/layer").asText());
         assertEquals("Mann", res.at("/query/operands/2/wrap/key").asText());
-        assertEquals(true, res.at("/query/operands/3").isMissingNode());
+        assertTrue(res.at("/query/operands/3").isMissingNode());
     }
 
 
@@ -279,7 +278,7 @@
                 .asText());
         assertEquals("Sonne", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("Mond", res.at("/query/operands/1/wrap/key").asText());
-        assertEquals(true, res.at("/query/operands/2").isMissingNode());
+        assertTrue(res.at("/query/operands/2").isMissingNode());
 
         query = "(Sonne scheint) oder Mond";
         qs.setQuery(query, "cosmas2");
@@ -295,7 +294,7 @@
         assertEquals("scheint", res.at("/query/operands/0/operands/1/wrap/key")
                 .asText());
         assertEquals("Mond", res.at("/query/operands/1/wrap/key").asText());
-        assertEquals(true, res.at("/query/operands/2").isMissingNode());
+        assertTrue(res.at("/query/operands/2").isMissingNode());
 
         query = "(Sonne scheint) oder (Mond scheint)";
         qs.setQuery(query, "cosmas2");
@@ -317,7 +316,7 @@
                 .asText());
         assertEquals("scheint", res.at("/query/operands/1/operands/1/wrap/key")
                 .asText());
-        assertEquals(true, res.at("/query/operands/2").isMissingNode());
+        assertTrue(res.at("/query/operands/2").isMissingNode());
     }
 
 
@@ -331,8 +330,8 @@
         assertEquals("koral:group", res.at("/query/@type").asText());
         assertEquals("operation:sequence", res.at("/query/operation").asText());
 
-        assertEquals(false, res.at("/query/inOrder").isMissingNode());
-        assertEquals(false, res.at("/query/inOrder").asBoolean());
+        assertFalse(res.at("/query/inOrder").isMissingNode());
+        assertFalse(res.at("/query/inOrder").asBoolean());
 
         assertEquals("cosmas:distance", res.at("/query/distances/0/@type")
                 .asText());
@@ -343,8 +342,8 @@
         assertEquals("operation:disjunction",
                 res.at("/query/operands/0/operation").asText());
 
-        assertEquals(false, res.at("/query/operands/0/inOrder").isMissingNode());
-        assertEquals(false, res.at("/query/operands/0/inOrder").asBoolean());
+        assertFalse(res.at("/query/operands/0/inOrder").isMissingNode());
+        assertFalse(res.at("/query/operands/0/inOrder").asBoolean());
 
         assertEquals("Sonne", res.at("/query/operands/0/operands/0/wrap/key")
                 .asText());
@@ -359,8 +358,8 @@
         res = mapper.readTree(qs.toJSON());
         assertEquals("koral:group", res.at("/query/@type").asText());
 
-        assertEquals(false, res.at("/query/inOrder").isMissingNode());
-        assertEquals(false, res.at("/query/inOrder").asBoolean());
+        assertFalse(res.at("/query/inOrder").isMissingNode());
+        assertFalse(res.at("/query/inOrder").asBoolean());
 
         assertEquals("operation:sequence", res.at("/query/operation").asText());
         assertEquals("cosmas:distance", res.at("/query/distances/0/@type")
@@ -374,8 +373,8 @@
         assertEquals("operation:disjunction",
                 res.at("/query/operands/1/operation").asText());
 
-        assertEquals(false, res.at("/query/operands/1/inOrder").isMissingNode());
-        assertEquals(false, res.at("/query/operands/1/inOrder").asBoolean());
+        assertFalse(res.at("/query/operands/1/inOrder").isMissingNode());
+        assertFalse(res.at("/query/operands/1/inOrder").asBoolean());
 
         assertEquals("Sonne", res.at("/query/operands/1/operands/0/wrap/key")
                 .asText());
@@ -389,8 +388,8 @@
         assertEquals("koral:group", res.at("/query/@type").asText());
         assertEquals("operation:sequence", res.at("/query/operation").asText());
 
-        assertEquals(false, res.at("/query/inOrder").isMissingNode());
-        assertEquals(false, res.at("/query/inOrder").asBoolean());
+        assertFalse(res.at("/query/inOrder").isMissingNode());
+        assertFalse(res.at("/query/inOrder").asBoolean());
 
         assertEquals("cosmas:distance", res.at("/query/distances/0/@type")
                 .asText());
@@ -404,8 +403,8 @@
         assertEquals("operation:sequence", res
                 .at("/query/operands/1/operation").asText());
 
-        assertEquals(false, res.at("/query/operands/1/inOrder").isMissingNode());
-        assertEquals(false, res.at("/query/operands/1/inOrder").asBoolean());
+        assertFalse(res.at("/query/operands/1/inOrder").isMissingNode());
+        assertFalse(res.at("/query/operands/1/inOrder").asBoolean());
 
         assertEquals("cosmas:distance",
                 res.at("/query/operands/1/distances/0/@type").asText());
@@ -417,9 +416,9 @@
         assertEquals("koral:group", res
                 .at("/query/operands/1/operands/1/@type").asText());
 
-        assertEquals(false, res.at("/query/operands/1/operands/1/inOrder")
+        assertFalse(res.at("/query/operands/1/operands/1/inOrder")
                 .isMissingNode());
-        assertEquals(false, res.at("/query/operands/1/operands/1/inOrder")
+        assertFalse(res.at("/query/operands/1/operands/1/inOrder")
                 .asBoolean());
 
         assertEquals("operation:disjunction",
@@ -445,7 +444,7 @@
         assertEquals("t", res.at("/query/distances/0/key").asText());
         assertEquals(0, res.at("/query/distances/0/min").asInt());
         assertEquals(0, res.at("/query/distances/0/max").asInt());
-        assertEquals(true, res.at("/query/distances/0/exclude").asBoolean());
+        assertTrue(res.at("/query/distances/0/exclude").asBoolean());
         assertEquals("koral:token", res.at("/query/operands/0/@type").asText());
         assertEquals("Sonne", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("Mond", res.at("/query/operands/1/wrap/key").asText());
@@ -460,7 +459,7 @@
         assertEquals("t", res.at("/query/distances/0/key").asText());
         assertEquals(0, res.at("/query/distances/0/min").asInt());
         assertEquals(0, res.at("/query/distances/0/max").asInt());
-        assertEquals(true, res.at("/query/distances/0/exclude").asBoolean());
+        assertTrue(res.at("/query/distances/0/exclude").asBoolean());
         assertEquals("koral:token", res.at("/query/operands/0/@type").asText());
         assertEquals("Sonne", res.at("/query/operands/0/wrap/key").asText());
         assertEquals("koral:group", res.at("/query/operands/1/@type").asText());
@@ -471,7 +470,7 @@
         assertEquals("t", res.at("/query/operands/1/distances/0/key").asText());
         assertEquals(0, res.at("/query/operands/1/distances/0/min").asInt());
         assertEquals(0, res.at("/query/operands/1/distances/0/max").asInt());
-        assertEquals(true, res.at("/query/operands/1/distances/0/exclude")
+        assertTrue(res.at("/query/operands/1/distances/0/exclude")
                 .asBoolean());
         assertEquals("Mond", res.at("/query/operands/1/operands/0/wrap/key")
                 .asText());
@@ -488,7 +487,7 @@
         assertEquals("t", res.at("/query/distances/0/key").asText());
         assertEquals(0, res.at("/query/distances/0/min").asInt());
         assertEquals(0, res.at("/query/distances/0/max").asInt());
-        assertEquals(true, res.at("/query/distances/0/exclude").asBoolean());
+        assertTrue(res.at("/query/distances/0/exclude").asBoolean());
         assertEquals("koral:group", res.at("/query/operands/0/@type").asText());
         assertEquals("operation:sequence", res
                 .at("/query/operands/0/operation").asText());
@@ -497,7 +496,7 @@
         assertEquals("t", res.at("/query/operands/0/distances/0/key").asText());
         assertEquals(0, res.at("/query/operands/0/distances/0/min").asInt());
         assertEquals(0, res.at("/query/operands/0/distances/0/max").asInt());
-        assertEquals(true, res.at("/query/operands/0/distances/0/exclude")
+        assertTrue(res.at("/query/operands/0/distances/0/exclude")
                 .asBoolean());
         assertEquals("Sonne", res.at("/query/operands/0/operands/0/wrap/key")
                 .asText());
@@ -520,7 +519,7 @@
         assertEquals("w", res.at("/query/distances/0/key").asText());
         assertEquals(1, res.at("/query/distances/0/boundary/min").asInt());
         assertEquals(4, res.at("/query/distances/0/boundary/max").asInt());
-        assertEquals(true, res.at("/query/inOrder").asBoolean());
+        assertTrue(res.at("/query/inOrder").asBoolean());
         assertEquals("koral:group", res.at("/query/operands/0/@type").asText());
         assertEquals("operation:class", res.at("/query/operands/0/operation")
                 .asText());
@@ -548,7 +547,7 @@
         assertEquals("p", res.at("/query/distances/2/key").asText());
         assertEquals(1, res.at("/query/distances/2/boundary/min").asInt());
         assertEquals(3, res.at("/query/distances/2/boundary/max").asInt());
-        assertEquals(true, res.at("/query/inOrder").asBoolean());
+        assertTrue(res.at("/query/inOrder").asBoolean());
         assertEquals("koral:group", res.at("/query/operands/0/@type").asText());
         assertEquals("operation:class", res.at("/query/operands/0/operation")
                 .asText());
@@ -577,7 +576,7 @@
         assertEquals("p", res.at("/query/distances/2/key").asText());
         assertEquals(1, res.at("/query/distances/2/boundary/min").asInt());
         assertEquals(3, res.at("/query/distances/2/boundary/max").asInt());
-        assertEquals(true, res.at("/query/inOrder").asBoolean());
+        assertTrue(res.at("/query/inOrder").asBoolean());
         assertEquals("koral:group", res.at("/query/operands/0/@type").asText());
         assertEquals("operation:class", res.at("/query/operands/0/operation")
                 .asText());
@@ -625,7 +624,7 @@
                 .asText());
         assertEquals("Mond", res.at("/query/operands/1/operands/0/wrap/key")
                 .asText());
-        assertEquals(false, res.at("/query/inOrder").asBoolean());
+        assertFalse(res.at("/query/inOrder").asBoolean());
     }
 
 
@@ -641,7 +640,7 @@
         assertEquals("w", res.at("/query/distances/0/key").asText());
         assertEquals(1, res.at("/query/distances/0/boundary/min").asInt());
         assertEquals(4, res.at("/query/distances/0/boundary/max").asInt());
-        assertEquals(true, res.at("/query/inOrder").asBoolean());
+        assertTrue(res.at("/query/inOrder").asBoolean());
         assertEquals("koral:group", res.at("/query/operands/0/@type").asText());
         assertEquals("operation:class", res.at("/query/operands/0/operation")
                 .asText());
@@ -698,7 +697,7 @@
         assertEquals("w", res.at("/query/distances/0/key").asText());
         assertEquals(0, res.at("/query/distances/0/boundary/min").asInt());
         assertEquals(4, res.at("/query/distances/0/boundary/max").asInt());
-        assertEquals(true, res.at("/query/inOrder").asBoolean());
+        assertTrue(res.at("/query/inOrder").asBoolean());
         assertEquals("koral:group", res.at("/query/operands/1/@type").asText());
         assertEquals("operation:class", res.at("/query/operands/1/operation")
                 .asText());
@@ -753,7 +752,7 @@
                 .asInt());
         assertEquals(5, res.at("/query/operands/0/distances/0/boundary/max")
                 .asInt());
-        assertEquals(false, res.at("/query/operands/0/inOrder").asBoolean());
+        assertFalse(res.at("/query/operands/0/inOrder").asBoolean());
         assertEquals("koral:token", res
                 .at("/query/operands/0/operands/0/@type").asText());
         assertEquals("der", res.at("/query/operands/0/operands/0/wrap/key")
@@ -771,7 +770,7 @@
         assertEquals("w", res.at("/query/distances/0/key").asText());
         assertEquals(0, res.at("/query/distances/0/boundary/min").asInt());
         assertEquals(10, res.at("/query/distances/0/boundary/max").asInt());
-        assertEquals(true, res.at("/query/inOrder").asBoolean());
+        assertTrue(res.at("/query/inOrder").asBoolean());
         assertEquals("koral:group", res.at("/query/operands/0/@type").asText());
         assertEquals("operation:class", res.at("/query/operands/0/operation")
                 .asText());
@@ -806,9 +805,8 @@
                 5,
                 res.at("/query/operands/0/operands/0/operands/0/distances/0/boundary/max")
                         .asInt());
-        assertEquals(false,
-                res.at("/query/operands/0/operands/0/operands/0/inOrder")
-                        .asBoolean());
+        assertFalse(res.at("/query/operands/0/operands/0/operands/0/inOrder")
+                .asBoolean());
         assertEquals(
                 "koral:token",
                 res.at("/query/operands/0/operands/0/operands/0/operands/0/@type")
@@ -839,7 +837,7 @@
         assertEquals("w", res.at("/query/distances/0/key").asText());
         assertEquals(0, res.at("/query/distances/0/boundary/min").asInt());
         assertEquals(10, res.at("/query/distances/0/boundary/max").asInt());
-        assertEquals(true, res.at("/query/inOrder").asBoolean());
+        assertTrue(res.at("/query/inOrder").asBoolean());
         assertEquals("koral:group", res.at("/query/operands/1/@type").asText());
         assertEquals("operation:class", res.at("/query/operands/1/operation")
                 .asText());
@@ -874,9 +872,8 @@
                 5,
                 res.at("/query/operands/1/operands/0/operands/0/distances/0/boundary/max")
                         .asInt());
-        assertEquals(false,
-                res.at("/query/operands/1/operands/0/operands/0/inOrder")
-                        .asBoolean());
+        assertFalse(res.at("/query/operands/1/operands/0/operands/0/inOrder")
+                .asBoolean());
         assertEquals(
                 "koral:token",
                 res.at("/query/operands/1/operands/0/operands/0/operands/0/@type")
@@ -914,7 +911,7 @@
                 .asInt());
         assertEquals(5, res.at("/query/operands/0/distances/0/boundary/max")
                 .asInt());
-        assertEquals(false, res.at("/query/operands/0/inOrder").asBoolean());
+        assertFalse(res.at("/query/operands/0/inOrder").asBoolean());
         assertEquals("koral:token", res
                 .at("/query/operands/0/operands/0/@type").asText());
         assertEquals("der", res.at("/query/operands/0/operands/0/wrap/key")
@@ -1362,7 +1359,7 @@
                 res.at("/query/operands/0/operands/1/operation").asText());
         assertEquals("frames:startsWith",
                 res.at("/query/operands/0/operands/1/frames/0").asText());
-        assertEquals(true, res.at("/query/operands/0/operands/1/exclude")
+        assertTrue(res.at("/query/operands/0/operands/1/exclude")
                 .asBoolean());
         assertEquals("koral:span",
                 res.at("/query/operands/0/operands/1/operands/0/@type")
@@ -1467,7 +1464,7 @@
                 res.at("/query/operands/0/operands/1/operation").asText());
         assertEquals("frames:startsWith",
                 res.at("/query/operands/0/operands/1/frames/0").asText());
-        assertEquals(true, res.at("/query/operands/0/operands/1/exclude")
+        assertTrue(res.at("/query/operands/0/operands/1/exclude")
                 .asBoolean());
         assertEquals("koral:span",
                 res.at("/query/operands/0/operands/1/operands/0/@type")
@@ -1552,10 +1549,8 @@
                 "frames:startsWith",
                 res.at("/query/operands/0/operands/1/operands/0/operands/0/frames/0")
                         .asText());
-        assertEquals(
-                true,
-                res.at("/query/operands/0/operands/1/operands/0/operands/0/exclude")
-                        .asBoolean());
+        assertTrue(res.at("/query/operands/0/operands/1/operands/0/operands/0/exclude")
+                .asBoolean());
         assertEquals(
                 "koral:span",
                 res.at("/query/operands/0/operands/1/operands/0/operands/0/operands/0/@type")
@@ -1666,7 +1661,7 @@
         query = "MORPH(tt/p=\"\")";
         qs.setQuery(query, "cosmas2");
         res = mapper.readTree(qs.toJSON());
-        assertEquals(true, res.at("/query/@type").isMissingNode());
+        assertTrue(res.at("/query/@type").isMissingNode());
         assertEquals(StatusCodes.INCOMPATIBLE_OPERATOR_AND_OPERAND,
                 res.at("/errors/0/0").asInt());
         assertTrue(res
@@ -1678,7 +1673,7 @@
         query = "MORPH(tt/p=\"foo)";
         qs.setQuery(query, "cosmas2");
         res = mapper.readTree(qs.toJSON());
-        assertEquals(true, res.at("/query/@type").isMissingNode());
+        assertTrue(res.at("/query/@type").isMissingNode());
         assertEquals(StatusCodes.MALFORMED_QUERY, res.at("/errors/0/0").asInt());
         assertTrue(res.at("/errors/0/1").asText()
                 .startsWith("Early closing parenthesis"));
@@ -1686,7 +1681,7 @@
         query = "MORPH(tt/p=)";
         qs.setQuery(query, "cosmas2");
         res = mapper.readTree(qs.toJSON());
-        assertEquals(true, res.at("/query/@type").isMissingNode());
+        assertTrue(res.at("/query/@type").isMissingNode());
         assertEquals(StatusCodes.MALFORMED_QUERY, res.at("/errors/0/0").asInt());
         assertTrue(res.at("/errors/0/1").asText()
                 .startsWith("Early closing parenthesis"));
@@ -1703,7 +1698,7 @@
         assertEquals(129, res.at("/query/operands/0/classOut").asInt());
         assertEquals("operation:disjunction", res.at("/query/operands/1/operands/0/operation").asText());
         assertEquals("cosmas:distance", res.at("/query/distances/0/@type").asText());
-        assertEquals(true, res.at("/query/distances/0/exclude").asBoolean());
+        assertTrue(res.at("/query/distances/0/exclude").asBoolean());
         assertEquals("s", res.at("/query/distances/0/key").asText());
         assertEquals("operation:sequence", res.at("/query/operation").asText());
     }
diff --git a/src/test/java/de/ids_mannheim/korap/test/cosmas2/OPINTest.java b/src/test/java/de/ids_mannheim/korap/test/cosmas2/OPINTest.java
index 2b9bd68..c4636c1 100644
--- a/src/test/java/de/ids_mannheim/korap/test/cosmas2/OPINTest.java
+++ b/src/test/java/de/ids_mannheim/korap/test/cosmas2/OPINTest.java
@@ -156,11 +156,10 @@
         res = mapper.readTree(qs.toJSON());
         checkFocus(res);
         res = res.at("/query/operands/0");
-        
-        assertEquals(true,
-                res.at("/query/operands/0/classRefCheck").isMissingNode());
+
+        assertTrue(res.at("/query/operands/0/classRefCheck").isMissingNode());
         assertEquals("frames:matches", res.at("/frames/0").asText());
-        assertEquals(true, res.at("/frames/1").isMissingNode());
+        assertTrue(res.at("/frames/1").isMissingNode());
     }
 
     @Test
@@ -182,8 +181,7 @@
         
         assertEquals("frames:matches",
                 res.at("/operands/0/frames/0").asText());
-        assertEquals(true,
-                res.at("/operands/0/frames/1").isMissingNode());
+        assertTrue(res.at("/operands/0/frames/1").isMissingNode());
         assertEquals("operation:position",
                 res.at("/operands/0/operation").asText());
         
@@ -210,8 +208,7 @@
         assertEquals(130, res.at("/classIn/1").asInt());
         assertEquals("frames:matches",
                 res.at("/operands/0/frames/0").asText());
-        assertEquals(true,
-                res.at("/operands/0/frames/1").isMissingNode());
+        assertTrue(res.at("/operands/0/frames/1").isMissingNode());
         
         JsonNode res1 = res.at("/operands/0/operands/0");
         assertEquals("operation:class", res1.at("/operation").asText());