diff --git a/lib/client-core/src/main/java/org/apache/olingo/client/core/communication/header/ODataErrorResponseChecker.java b/lib/client-core/src/main/java/org/apache/olingo/client/core/communication/header/ODataErrorResponseChecker.java
index d79174c19..bd0bf499e 100644
--- a/lib/client-core/src/main/java/org/apache/olingo/client/core/communication/header/ODataErrorResponseChecker.java
+++ b/lib/client-core/src/main/java/org/apache/olingo/client/core/communication/header/ODataErrorResponseChecker.java
@@ -80,7 +80,8 @@ public final class ODataErrorResponseChecker {
             statusLine.getReasonPhrase());
       }
 
-      if (statusLine.getStatusCode() >= 500 && (error.getDetails() == null || error.getDetails().isEmpty()) && 
+      if (statusLine.getStatusCode() >= 500 && error!= null && 
+          (error.getDetails() == null || error.getDetails().isEmpty()) && 
           (error.getInnerError() == null || error.getInnerError().size() == 0)) {
         result = new ODataServerErrorException(statusLine);
       } else {
diff --git a/lib/client-core/src/main/java/org/apache/olingo/client/core/communication/request/batch/ODataBatchUtilities.java b/lib/client-core/src/main/java/org/apache/olingo/client/core/communication/request/batch/ODataBatchUtilities.java
index bca612fb9..b2c5c40e0 100644
--- a/lib/client-core/src/main/java/org/apache/olingo/client/core/communication/request/batch/ODataBatchUtilities.java
+++ b/lib/client-core/src/main/java/org/apache/olingo/client/core/communication/request/batch/ODataBatchUtilities.java
@@ -137,7 +137,7 @@ public class ODataBatchUtilities {
 
             notEndLine = isNotEndLine(controller, currentLine);
 
-            if (notEndLine && os != null) {
+            if (notEndLine && os != null && currentLine!=null) {
               os.write(currentLine.getBytes(Constants.UTF8));
               os.write(ODataStreamer.CRLF);
             }
@@ -256,11 +256,14 @@ public class ODataBatchUtilities {
   public static Map.Entry<Integer, String> readResponseLine(final ODataBatchLineIterator iterator) {
     final String line = readBatchPart(new ODataBatchController(iterator, null), 1);
     LOG.debug("Response line '{}'", line);
+    
+    if(line !=null){
 
-    final Matcher matcher = RESPONSE_PATTERN.matcher(line.trim());
+      final Matcher matcher = RESPONSE_PATTERN.matcher(line.trim());
 
-    if (matcher.matches()) {
-      return new AbstractMap.SimpleEntry<Integer, String>(Integer.valueOf(matcher.group(1)), matcher.group(2));
+      if (matcher.matches()) {
+        return new AbstractMap.SimpleEntry<Integer, String>(Integer.valueOf(matcher.group(1)), matcher.group(2));
+      }
     }
 
     throw new IllegalArgumentException("Invalid response line '" + line + "'");
diff --git a/lib/client-core/src/main/java/org/apache/olingo/client/core/metadatavalidator/CsdlTypeValidator.java b/lib/client-core/src/main/java/org/apache/olingo/client/core/metadatavalidator/CsdlTypeValidator.java
index 4eef83610..af35bc657 100644
--- a/lib/client-core/src/main/java/org/apache/olingo/client/core/metadatavalidator/CsdlTypeValidator.java
+++ b/lib/client-core/src/main/java/org/apache/olingo/client/core/metadatavalidator/CsdlTypeValidator.java
@@ -19,10 +19,8 @@
 package org.apache.olingo.client.core.metadatavalidator;
 
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
-import java.util.Set;
 import java.util.Map.Entry;
 
 import org.apache.olingo.client.api.edm.xml.XMLMetadata;
diff --git a/lib/client-core/src/main/java/org/apache/olingo/client/core/uri/FilterFunction.java b/lib/client-core/src/main/java/org/apache/olingo/client/core/uri/FilterFunction.java
index 614f44b0a..36f37059e 100644
--- a/lib/client-core/src/main/java/org/apache/olingo/client/core/uri/FilterFunction.java
+++ b/lib/client-core/src/main/java/org/apache/olingo/client/core/uri/FilterFunction.java
@@ -35,10 +35,12 @@ public class FilterFunction implements FilterArg {
   @Override
   public String build() {
     final String[] strParams = params == null || params.length == 0 ? new String[0] : new String[params.length];
-    for (int i = 0; i < strParams.length; i++) {
-      strParams[i] = params[i].build();
+    if(params !=null){
+      for (int i = 0; i < strParams.length; i++) {
+        strParams[i] = params[i].build();
+      }
     }
-
+    
     return new StringBuilder(function).
             append('(').
             append(strParams.length == 0 ? StringUtils.EMPTY : StringUtils.join(strParams, ',')).
diff --git a/lib/server-core/src/main/java/org/apache/olingo/server/core/debug/DebugTabStacktrace.java b/lib/server-core/src/main/java/org/apache/olingo/server/core/debug/DebugTabStacktrace.java
index 310ec3ab9..72b4f51fc 100644
--- a/lib/server-core/src/main/java/org/apache/olingo/server/core/debug/DebugTabStacktrace.java
+++ b/lib/server-core/src/main/java/org/apache/olingo/server/core/debug/DebugTabStacktrace.java
@@ -63,8 +63,10 @@ public class DebugTabStacktrace implements DebugTab {
 
     gen.writeFieldName("stacktrace");
     gen.writeStartArray();
-    for (final StackTraceElement stackTraceElement : exception.getStackTrace()) {
-      appendJsonStackTraceElement(gen, stackTraceElement);
+    if(exception != null){
+      for (final StackTraceElement stackTraceElement : exception.getStackTrace()) {
+        appendJsonStackTraceElement(gen, stackTraceElement);
+      }
     }
     gen.writeEndArray();
 
diff --git a/lib/server-core/src/main/java/org/apache/olingo/server/core/serializer/json/ServiceDocumentJsonSerializer.java b/lib/server-core/src/main/java/org/apache/olingo/server/core/serializer/json/ServiceDocumentJsonSerializer.java
index 75f511577..6cc2c1e15 100644
--- a/lib/server-core/src/main/java/org/apache/olingo/server/core/serializer/json/ServiceDocumentJsonSerializer.java
+++ b/lib/server-core/src/main/java/org/apache/olingo/server/core/serializer/json/ServiceDocumentJsonSerializer.java
@@ -71,12 +71,13 @@ public class ServiceDocumentJsonSerializer {
     }
 
     gen.writeArrayFieldStart(Constants.VALUE);
-
-    final EdmEntityContainer container = metadata.getEdm().getEntityContainer();
-    if (container != null) {
-      writeEntitySets(gen, container);
-      writeFunctionImports(gen, container);
-      writeSingletons(gen, container);
+    if(metadata != null){
+      final EdmEntityContainer container = metadata.getEdm().getEntityContainer();
+      if (container != null) {
+        writeEntitySets(gen, container);
+        writeFunctionImports(gen, container);
+        writeSingletons(gen, container);
+      }
     }
   }