diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/AbstractSyntaxTree.java b/src/main/java/de/ids_mannheim/korap/query/serialize/AbstractSyntaxTree.java
index 4a2ae95..7b1b01e 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/AbstractSyntaxTree.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/AbstractSyntaxTree.java
@@ -11,17 +11,21 @@
 import org.antlr.runtime.tree.Tree;
 import org.antlr.v4.runtime.tree.ParseTree;
 import org.apache.commons.lang.StringUtils;
+import org.slf4j.Logger;
 
 import de.ids_mannheim.korap.util.QueryException;
 
 public abstract class AbstractSyntaxTree {
 	
-	public abstract Map<String, Object> getRequestMap();
-
 	public abstract void process(String query) throws QueryException;
 	
 	public static final Integer MAXIMUM_DISTANCE = 100; 
-	
+
+	Logger log;
+	/**
+	 *  The query
+	 */
+	String query;
 	/**
 	 * Top-level map representing the whole request.
 	 */
@@ -49,9 +53,20 @@
 	ParseTree currentNode = null;
 	Integer stackedObjects = 0;
 	ArrayList<String> errorMsgs = new ArrayList<String>();
-	ArrayList<String> userWarnings = new ArrayList<String>();
-	ArrayList<String> backendWarnings = new ArrayList<String>();
-
+	ArrayList<String> warnings = new ArrayList<String>();
+	ArrayList<String> announcements = new ArrayList<String>();
+	
+	AbstractSyntaxTree() {
+		requestMap.put("@context", "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld");
+		requestMap.put("errors", errorMsgs);
+		requestMap.put("warnings", warnings);
+		requestMap.put("announcements", announcements);
+	}
+	
+	public Map<String, Object> getRequestMap() {
+		return requestMap;
+	}
+	
 	protected LinkedHashMap<String, Object> makeSpan() {
 		LinkedHashMap<String, Object> span = new LinkedHashMap<String, Object>();
 		span.put("@type", "korap:span");
@@ -112,7 +127,7 @@
 		group.put("boundary", makeBoundary(min, max));
 		group.put("min", min);
 		group.put("max", max);
-		backendWarnings.add("Deprecated 2014-07-24: 'min' and 'max' to be supported until 6 months from deprecation date.");
+		announcements.add("Deprecated 2014-07-24: 'min' and 'max' to be supported until 6 months from deprecation date.");
 		return group;
 	}
 	
@@ -163,7 +178,7 @@
 		group.put("boundary", makeBoundary(min, max));
 		group.put("min", min);
 		group.put("max", max);
-		backendWarnings.add("Deprecated 2014-07-24: 'min' and 'max' to be supported until 6 months from deprecation date.");
+		announcements.add("Deprecated 2014-07-24: 'min' and 'max' to be supported until 6 months from deprecation date.");
 		return group;
 	}
 	
diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/Antlr4AbstractSyntaxTree.java b/src/main/java/de/ids_mannheim/korap/query/serialize/Antlr4AbstractSyntaxTree.java
index 25d0fb9..8b726c0 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/Antlr4AbstractSyntaxTree.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/Antlr4AbstractSyntaxTree.java
@@ -11,7 +11,6 @@
 
 public abstract class Antlr4AbstractSyntaxTree extends AbstractSyntaxTree {
 
-
 	/**
 	 * Parser object deriving the ANTLR parse tree.
 	 */
diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/AqlTree.java b/src/main/java/de/ids_mannheim/korap/query/serialize/AqlTree.java
index 8cbaf19..51e5d6e 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/AqlTree.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/AqlTree.java
@@ -15,10 +15,10 @@
 import org.antlr.v4.runtime.CharStream;
 import org.antlr.v4.runtime.CommonTokenStream;
 import org.antlr.v4.runtime.Lexer;
-import org.antlr.v4.runtime.Parser;
 import org.antlr.v4.runtime.ParserRuleContext;
 import org.antlr.v4.runtime.tree.ParseTree;
 import org.slf4j.LoggerFactory;
+import org.slf4j.Logger;
 
 import de.ids_mannheim.korap.query.annis.AqlLexer;
 import de.ids_mannheim.korap.query.annis.AqlParser;
@@ -30,8 +30,7 @@
  *
  */
 public class AqlTree extends Antlr4AbstractSyntaxTree {
-	private org.slf4j.Logger log = LoggerFactory
-			.getLogger(AqlTree.class);
+	private static Logger log = LoggerFactory.getLogger(AqlTree.class);
 	/**
 	 * Flag that indicates whether token fields or meta fields are currently being processed
 	 */
@@ -87,7 +86,6 @@
 	 * @param parser The ANTLR parser instance that generated the parse tree
 	 */
 	public AqlTree(String query) {
-		requestMap.put("@context", "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld");
 		try {
 			process(query);
 		} catch (QueryException e) {
@@ -96,12 +94,6 @@
 		System.out.println(">>> "+requestMap.get("query")+" <<<");
 	}
 
-
-	@Override
-	public Map<String, Object> getRequestMap() {
-		return requestMap;
-	}
-
 	@Override
 	public void process(String query) throws QueryException {
 		ParseTree tree = parseAnnisQuery(query);
diff --git a/src/main/java/de/ids_mannheim/korap/query/serialize/CosmasTree.java b/src/main/java/de/ids_mannheim/korap/query/serialize/CosmasTree.java
index 4da63da..9d0adb8 100644
--- a/src/main/java/de/ids_mannheim/korap/query/serialize/CosmasTree.java
+++ b/src/main/java/de/ids_mannheim/korap/query/serialize/CosmasTree.java
@@ -25,7 +25,6 @@
 
     private static Logger log = LoggerFactory.getLogger(CosmasTree.class);
 
-    String query;
     LinkedList<LinkedHashMap[]> toWrapStack = new LinkedList<LinkedHashMap[]>();
     /**
      * Field for repetition query (Kleene + or * operations, or min/max queries: {2,4}
@@ -51,9 +50,6 @@
     int wrapFirstOpInClass = -1;
     int wrapSecondOpInClass = -1;
 
-    Tree cosmasTree;
-
-    LinkedHashMap<String, Object> treeMap = new LinkedHashMap<String, Object>();
     /**
      * Keeps track of all visited nodes in a tree
      */
@@ -91,12 +87,6 @@
     }
 
     @Override
-    public Map<String, Object> getRequestMap() {
-        return this.requestMap;
-    }
-
-
-    @Override
     public void process(String query) throws QueryException {
         Tree tree = null;
         try {
@@ -108,8 +98,6 @@
         }
         log.info("Processing CosmasII query");
         System.out.println("Processing Cosmas");
-        requestMap.put("@context", "http://ids-mannheim.de/ns/KorAP/json-ld/v0.1/context.jsonld");
-//		prepareContext(requestMap);
         processNode(tree);
         log.info(requestMap.toString());
     }