DATACMNS-828 - Fixed potential NullPointerException in ResultProcessor.

ResultProcessor.processResult(…) now explicitly handles null values to prevent IllegalArgumentExceptions being provoked in the ProjectionFactory which occurred if null values were handed down to it.

Author: odrotbohm

src/main/java/org/springframework/data/repository/query/ResultProcessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 the original author or authors.
+ * Copyright 2015-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -121,7 +121,7 @@ public <T> T processResult(Object source) {
 	@SuppressWarnings("unchecked")
 	public <T> T processResult(Object source, Converter<Object, Object> preparingConverter) {
 
-		if (type.isInstance(source) || !type.isProjecting()) {
+		if (source == null || type.isInstance(source) || !type.isProjecting()) {
 			return (T) source;
 		}
 

src/test/java/org/springframework/data/repository/query/ResultProcessorUnitTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015 the original author or authors.
+ * Copyright 2015-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -186,6 +186,14 @@ public Object convert(Object source) {
 		assertThat(result, is(instanceOf(SampleDTO.class)));
 	}
 
+	/**
+	 * @see DATACMNS-828
+	 */
+	@Test
+	public void returnsNullResultAsIs() throws Exception {
+		assertThat(getProcessor("findOneDto").processResult(null), is(nullValue()));
+	}
+
 	private static ResultProcessor getProcessor(String methodName, Class<?>... parameters) throws Exception {
 		return getQueryMethod(methodName, parameters).getResultProcessor();
 	}