6738181: api/java_awt/Toolkit/index.html#GetAWTEventListeners Fails with:empty array returned unexpectedly

Redirect getAWTEventListeners(long l) from Headless to underlying toolkit.

Reviewed-by: art

jdk/src/share/classes/sun/awt/HeadlessToolkit.java

@@ -456,6 +456,10 @@ public class HeadlessToolkit extends Toolkit
         return tk.getAWTEventListeners();
     }
 
+    public AWTEventListener[] getAWTEventListeners(long eventMask) {
+        return tk.getAWTEventListeners(eventMask);
+    }
+
     public boolean isDesktopSupported() {
         return false;
     }

jdk/test/java/awt/Toolkit/Headless/AWTEventListener/AWTListener.java

@@ -0,0 +1,48 @@
+/*
+  @test
+  @bug 6738181
+  @library ../../../regtesthelpers
+  @build Sysout
+  @summary Toolkit.getAWTEventListeners returns empty array
+  @author andrei dmitriev: area=awt.headless
+  @run main/othervm -Djava.awt.headless=true AWTListener
+*/
+
+/**
+ * In a headless mode add a listener for container events.
+ * Check if a single listener is still assigned to the Toolkit class.
+ */
+
+import java.awt.*;
+import java.awt.event.*;
+import test.java.awt.regtesthelpers.Sysout;
+
+public class AWTListener {
+    public static void main(String []s) {
+        Toolkit toolkit = Toolkit.getDefaultToolkit();
+
+        AWTEventListener orig = new AWTEventListener() {
+                public void eventDispatched(AWTEvent event) { }
+            };
+
+        Sysout.println("Test: listener to add = " +orig);
+        toolkit.addAWTEventListener(orig, AWTEvent.CONTAINER_EVENT_MASK);
+
+        for (AWTEventListener l: toolkit.getAWTEventListeners()){
+            Sysout.println("Test: listener = " +l+" ");
+        }
+
+        if ( toolkit.getAWTEventListeners().length == 0 ) {
+            throw new RuntimeException("Case 1. An empty array returned unexpectedly");
+        }
+
+        for (AWTEventListener l: toolkit.getAWTEventListeners(AWTEvent.CONTAINER_EVENT_MASK)){
+            Sysout.println("Test: listener = " +l);
+         }
+
+        if ( toolkit.getAWTEventListeners(AWTEvent.CONTAINER_EVENT_MASK).length == 0 ) {
+            throw new RuntimeException("Case 2. An empty array returned unexpectedly");
+        }
+        Sysout.println("Test PASSED");
+    }
+}