diff --git a/google-http-client/src/main/java/com/google/api/client/util/GenericData.java b/google-http-client/src/main/java/com/google/api/client/util/GenericData.java
index c6635f89e..a2af1eae7 100644
--- a/google-http-client/src/main/java/com/google/api/client/util/GenericData.java
+++ b/google-http-client/src/main/java/com/google/api/client/util/GenericData.java
@@ -80,9 +80,9 @@ public final boolean containsKey(Object name) {
       return false;
     }
     String fieldName = (String) name;
-    boolean hasFieldInfo = classInfo.hasFieldInfo(fieldName);
-    if (hasFieldInfo) {
-      return true;
+    FieldInfo fieldInfo = classInfo.getFieldInfo(fieldName);
+    if (fieldInfo != null) {
+      return fieldInfo.getValue(this) != null;
     }
     if (classInfo.getIgnoreCase()) {
       fieldName = fieldName.toLowerCase(Locale.US);
diff --git a/google-http-client/src/test/java/com/google/api/client/util/GenericDataTest.java b/google-http-client/src/test/java/com/google/api/client/util/GenericDataTest.java
index fd6547bb6..828cda414 100644
--- a/google-http-client/src/test/java/com/google/api/client/util/GenericDataTest.java
+++ b/google-http-client/src/test/java/com/google/api/client/util/GenericDataTest.java
@@ -155,9 +155,17 @@ public void testPutIgnoreCase_class() {
   @Test
   public void testGetIgnoreCase_class() {
     MyData data = new MyData();
+    assertFalse(data.containsKey("FIELDA"));
+    assertFalse(data.containsKey("FieldA"));
+    assertFalse(data.keySet().contains("FieldA"));
     data.fieldA = "someValue";
     assertTrue(data.containsKey("FIELDA"));
+    assertTrue(data.containsKey("FieldA"));
+    assertTrue(data.keySet().contains("FieldA"));
     assertEquals("someValue", data.get("FIELDA"));
+    data.fieldA = null;
+    assertFalse(data.containsKey("FIELDA"));
+    assertFalse(data.keySet().contains("FieldA"));
   }
 
   @Test
diff --git a/pom.xml b/pom.xml
index 14941b440..b67f08e88 100644
--- a/pom.xml
+++ b/pom.xml
@@ -405,19 +405,6 @@
           <artifactId>maven-enforcer-plugin</artifactId>
           <version>3.5.0</version>
         </plugin>
-        <plugin>
-          <groupId>org.apache.maven.plugins</groupId>
-          <artifactId>maven-source-plugin</artifactId>
-          <version>3.3.1</version>
-          <executions>
-            <execution>
-              <id>attach-sources</id>
-              <goals>
-                <goal>jar-no-fork</goal>
-              </goals>
-            </execution>
-          </executions>
-        </plugin>
       </plugins>
     </pluginManagement>
     <plugins>