Merge pull request hazelcast#6185 from jerrinot/fix/NPE_onIntefacesWh…

…enFieldDoesNotExist/maintanance-3.x

[Backport] - Do not throw NPE when intermediate field is an interface

hazelcast/src/main/java/com/hazelcast/query/impl/getters/ReflectionHelper.java

@@ -175,7 +175,7 @@ private static Getter createGetter(Object obj, String attribute) {
                     }
                     if (localGetter == null) {
                         Class c = clazz;
-                        while (!Object.class.equals(c)) {
+                        while (!c.isInterface() && !Object.class.equals(c)) {
                             try {
                                 final Field field = c.getDeclaredField(name);
                                 field.setAccessible(true);

hazelcast/src/test/java/com/hazelcast/query/impl/getters/ReflectionHelperTest.java

@@ -1,13 +1,16 @@
 package com.hazelcast.query.impl.getters;
 
+import com.hazelcast.query.QueryException;
 import com.hazelcast.query.impl.AttributeType;
 import com.hazelcast.test.HazelcastParallelClassRunner;
 import com.hazelcast.test.annotation.QuickTest;
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
 import org.junit.runner.RunWith;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.fail;
 
 @RunWith(HazelcastParallelClassRunner.class)
 @Category(QuickTest.class)
@@ -19,4 +22,31 @@ public void test_getAttributeType() throws Exception {
 
         assertNull(attributeType);
     }
+
+
+    @Test
+    public void extractValue_whenIntermediateFieldIsInterfaceAndDoesNotContainField_thenThrowIllegalArgumentException() throws Exception {
+        OuterObject object = new OuterObject();
+        try {
+            ReflectionHelper.extractValue(object, "emptyInterface.doesNotExist");
+            fail("Non-existing field has been ignored");
+        } catch (QueryException e) {
+            // createGetter() method is catching everything throwable and wraps it in QueryException
+            // I don't think it's the right thing to do, but I don't want to change this behaviour.
+            // Hence I have to use try/catch in this test instead of just declaring
+            // IllegalArgumentException as expected exception.
+            assertEquals(IllegalArgumentException.class, e.getCause().getClass());
+        }
+    }
+
+
+
+    private static class OuterObject {
+        private EmptyInterface emptyInterface;
+    }
+
+    private interface EmptyInterface {
+
+    }
+
 }