Fixed list access services and added tests.

Change-Id: Idf460f41c09393231d5b83d8d20c245c9eaa34d2
diff --git a/core/pom.xml b/core/pom.xml
index e82c424..4c5d03c 100644
--- a/core/pom.xml
+++ b/core/pom.xml
@@ -93,6 +93,7 @@
 		    <plugin>
 		      <groupId>org.apache.maven.plugins</groupId>
 		      <artifactId>maven-source-plugin</artifactId>
+		      <version>3.0.1</version>
 		      <executions>
 		        <execution>
 		          <id>attach-sources</id>
diff --git a/core/src/main/java/de/ids_mannheim/korap/utils/ParameterChecker.java b/core/src/main/java/de/ids_mannheim/korap/utils/ParameterChecker.java
index a1e2a51..6d928f4 100644
--- a/core/src/main/java/de/ids_mannheim/korap/utils/ParameterChecker.java
+++ b/core/src/main/java/de/ids_mannheim/korap/utils/ParameterChecker.java
@@ -12,22 +12,23 @@
                     "null");
         }
     }
-    
+
     public static void checkStringValue (String string, String name)
             throws KustvaktException {
-        if (string == null ) {
+        if (string == null) {
             throw new KustvaktException(StatusCodes.INVALID_ARGUMENT, name,
                     "null");
         }
-        else if (string.isEmpty()){
+        else if (string.isEmpty()) {
             throw new KustvaktException(StatusCodes.INVALID_ARGUMENT, name,
                     "empty");
         }
     }
 
-    public static void checkIntegerValue (int integer, String name) throws KustvaktException {
+    public static void checkIntegerValue (int integer, String name)
+            throws KustvaktException {
         if (integer == 0) {
-            throw new KustvaktException(StatusCodes.INVALID_ARGUMENT, name,
+            throw new KustvaktException(StatusCodes.MISSING_ARGUMENT, name,
                     "0");
         }
     }