Switching between Metal L&F and Synth L&F by Loading the Synth XML
file more than once throws Exception.
*********************************************
java.lang.NullPointerException
        at javax.swing.plaf.synth.SynthLookAndFeel.paintRegion(SynthLookAndFeel.java:345)
        at javax.swing.plaf.synth.SynthLookAndFeel.update(SynthLookAndFeel.java:309)
        at javax.swing.plaf.synth.SynthRootPaneUI.update(SynthRootPaneUI.java:76)
        at javax.swing.JComponent.paintComponent(JComponent.java:543)
        at javax.swing.JComponent.paint(JComponent.java:810)
        at javax.swing.JComponent.paintWithOffscreenBuffer(JComponent.java:4593)
        at javax.swing.JComponent.paintDoubleBuffered(JComponent.java:4546)
        at javax.swing.JComponent._paintImmediately(JComponent.java:4490)
        at javax.swing.JComponent.paintImmediately(JComponent.java:4293)
        at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:410)
        at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:117)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:178)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:454)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:214)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:163)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)
java.lang.NullPointerException
        at javax.swing.plaf.synth.SynthButtonUI.getPreferredSize(SynthButtonUI.java:276)
        at javax.swing.JComponent.getPreferredSize(JComponent.java:1277)
        at java.awt.FlowLayout.layoutContainer(FlowLayout.java:437)
        at java.awt.Container.layout(Container.java:1357)
        at java.awt.Container.doLayout(Container.java:1347)
        at java.awt.Container.validateTree(Container.java:1429)
        at java.awt.Container.validateTree(Container.java:1436)
        at java.awt.Container.validateTree(Container.java:1436)
        at java.awt.Container.validate(Container.java:1404)
        at javax.swing.RepaintManager.validateInvalidComponents(RepaintManager.java:353)
        at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:116)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:178)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:454)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:214)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:163)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)
java.lang.NullPointerException
        at javax.swing.plaf.synth.SynthButtonUI.getPreferredSize(SynthButtonUI.java:276)
        at javax.swing.JComponent.getPreferredSize(JComponent.java:1277)
        at java.awt.FlowLayout.layoutContainer(FlowLayout.java:437)
        at java.awt.Container.layout(Container.java:1357)
        at java.awt.Container.doLayout(Container.java:1347)
        at java.awt.Container.validateTree(Container.java:1429)
        at java.awt.Container.validateTree(Container.java:1436)
        at java.awt.Container.validateTree(Container.java:1436)
        at java.awt.Container.validate(Container.java:1404)
        at javax.swing.RepaintManager.validateInvalidComponents(RepaintManager.java:353)
        at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:116)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:178)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:454)
        at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:214)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:163)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:157)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:149)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:110)
 ********************************************

Steps to Reproduce:
---------------------
a)Compile all attached ".java" files.
b)Run attached "JButtonExample.java" with "Button.xml"
By Default Look and Feel is Synth

Program runs in Following Sequence.
1)After "Thread.sleep(4000)" Background color of "Button1" changes to "pink".
2)After "Thread.sleep(4000)" L&F changes to Metal Look and Feel.
3)After "Thread.sleep(4000)" we load the Synth XML File again and change
the L&F to Synth which throws the exception on Console,
 but Look and Feel changes to Synth Again whereas Background color of "Button1" still "pink" which should be
"yellow" as per the defination in "Button.xml" file. It gets changes only after clicking on "Button1"

Note:If we comment out "laf.load(JButtonExample.class.getResourceAsStream(xmlFile),JButtonExample.class);"
from "JButtonExample.java" at line 33 then there is no Exception on
Console but Background color problem for "Button1" still exist.