Switched to gmaven plus, it fixes random failures observer with its p…

…redecessor gmaven.

examples/pom.xml

@@ -184,16 +184,6 @@
     <outputDirectory>target/scala-${scala.binary.version}/classes</outputDirectory>
     <testOutputDirectory>target/scala-${scala.binary.version}/test-classes</testOutputDirectory>
     <plugins>
-      <plugin>
-        <groupId>org.codehaus.gmaven</groupId>
-        <artifactId>gmaven-plugin</artifactId>
-        <version>1.4</version>
-        <executions>
-          <execution>
-            <phase>none</phase>
-          </execution>
-        </executions>
-      </plugin>
       <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-deploy-plugin</artifactId>

pom.xml

@@ -267,16 +267,28 @@
       </snapshots>
     </pluginRepository>
   </pluginRepositories>
+
+  <dependencies>
   <!-- 
        This is a dummy dependency that is used along with the shading plug-in
        to create effective poms on publishing (see SPARK-3812).
   -->
-  <dependencies>
     <dependency>
       <groupId>org.spark-project.spark</groupId>
       <artifactId>unused</artifactId>
       <version>1.0.0</version>
     </dependency>
+    <!-- 
+         This depndency has been added to provided scope as it is needed for excuting build
+         specific groovy scripts using gmaven+ and not required for downstream project building
+         with spark.
+    -->
+    <dependency>
+      <groupId>org.codehaus.groovy</groupId>
+      <artifactId>groovy-all</artifactId>
+      <version>2.3.7</version>
+      <scope>provided</scope>
+    </dependency>
   </dependencies>
   <dependencyManagement>
     <dependencies>
@@ -1048,20 +1060,22 @@
 
       <!-- This plugin reads a file into maven property. And it lets us write groovy !! -->
       <plugin>
-        <groupId>org.codehaus.gmaven</groupId>
-        <artifactId>gmaven-plugin</artifactId>
-        <version>1.4</version>
+        <groupId>org.codehaus.gmavenplus</groupId>
+        <artifactId>gmavenplus-plugin</artifactId>
+        <version>1.2</version>
         <executions>
           <execution>
             <phase>process-test-classes</phase>
             <goals>
               <goal>execute</goal>
             </goals>
             <configuration>
-              <source>
+              <scripts>
+                <script><![CDATA[
                 def file = new File(project.properties.test_classpath_file)
                 project.properties.test_classpath = file.getText().split().join(":")
-              </source>
+                ]]></script>
+              </scripts>
             </configuration>
           </execution>
         </executions>

project/SparkBuild.scala

@@ -361,6 +361,7 @@ object TestSettings {
       .map { case (k,v) => s"-D$k=$v" }.toSeq,
     javaOptions in Test ++= "-Xmx3g -XX:PermSize=128M -XX:MaxNewSize=256m -XX:MaxPermSize=1g"
       .split(" ").toSeq,
+    // This places test scope jars on the classpath of executors during tests.
     javaOptions in Test += 
       "-Dspark.executor.extraClassPath=" + (fullClasspath in Test).value.files.
       map(_.getAbsolutePath).mkString(":").stripSuffix(":"),