6653511: JComponent.safelyGetGraphics() may sometimes return null

Reviewed-by: rupashka

src/share/classes/javax/swing/JComponent.java

@@ -5158,9 +5158,8 @@ public abstract class JComponent extends Container implements Serializable,
                 }
             }
         }
-
         try {
-            g = safelyGetGraphics(paintingComponent, c);
+            if ((g = safelyGetGraphics(paintingComponent, c)) != null) {
                 try {
                     if (hasBuffer) {
                         RepaintManager rm = RepaintManager.currentManager(
@@ -5175,16 +5174,16 @@ public abstract class JComponent extends Container implements Serializable,
                         } finally {
                             rm.endPaint();
                         }
-                }
-                else {
-                    g.setClip(paintImmediatelyClip.x,paintImmediatelyClip.y,
-                       paintImmediatelyClip.width,paintImmediatelyClip.height);
+                    } else {
+                        g.setClip(paintImmediatelyClip.x, paintImmediatelyClip.y,
+                                paintImmediatelyClip.width, paintImmediatelyClip.height);
                         paintingComponent.paint(g);
                     }
                 } finally {
                     g.dispose();
                 }
             }
+        }
         finally {
             // Reset the painting child for the parent components.
             if(paintingComponent != this) {