FULL PRODUCT VERSION :
java version "1.9.0-ea"
Java(TM) SE Runtime Environment (build 1.9.0-ea-b82)
Java HotSpot(TM) 64-Bit Server VM (build 1.9.0-ea-b82, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Wersja 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
Call to:

java.lang.management.ManagementFactory.getPlatformMBeanServer();

Fails with:
java.lang.NoClassDefFoundError: com/sun/management/internal/GarbageCollectorExtImpl

Actuall test case that I'm working with is initalization of Apache Common Java Caching System. This fails with trace:
java.lang.NoClassDefFoundError: com/sun/management/internal/GarbageCollectorExtImpl
        at sun.management.MemoryImpl.getMemoryManagers0(Native Method)
        at sun.management.MemoryImpl.getMemoryManagers(MemoryImpl.java:98)
        at sun.management.ManagementFactoryHelper.getGarbageCollectorMXBeans(ManagementFactoryHelper.java:130)
        at java.lang.management.DefaultPlatformMBeanProvider$4.nameToMBeanMap(DefaultPlatformMBeanProvider.java:185)
        at java.lang.management.ManagementFactory.lambda$getPlatformMBeanServer$0(ManagementFactory.java:478)
        at java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:269)
        at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
        at java.util.HashMap$ValueSpliterator.forEachRemaining(HashMap.java:1664)
        at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482)
        at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
        at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
        at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
        at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
        at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:430)
        at java.lang.management.ManagementFactory.getPlatformMBeanServer(ManagementFactory.java:479)
        at org.apache.commons.jcs.engine.control.CompositeCacheManager.initialize(CompositeCacheManager.java:262)
        at org.apache.commons.jcs.engine.control.CompositeCacheManager.getUnconfiguredInstance(CompositeCacheManager.java:214)
        at org.openstreetmap.josm.data.cache.JCSCacheManager.initialize(JCSCacheManager.java:117)
        at org.openstreetmap.josm.data.cache.JCSCacheManager.getCache(JCSCacheManager.java:148)
        at org.openstreetmap.josm.gui.layer.AbstractCachedTileSourceLayer.getCache(AbstractCachedTileSourceLayer.java:122)
        at org.openstreetmap.josm.gui.layer.AbstractCachedTileSourceLayer.getTileLoaderFactory(AbstractCachedTileSourceLayer.java:113)
        at org.openstreetmap.josm.gui.bbox.SlippyMapBBoxChooser.<init>(SlippyMapBBoxChooser.java:143)
        at org.openstreetmap.josm.gui.download.SlippyMapChooser.<init>(SlippyMapChooser.java:34)
        at org.openstreetmap.josm.gui.download.DownloadDialog.buildMainPanel(DownloadDialog.java:122)
        at org.openstreetmap.josm.gui.download.DownloadDialog.<init>(DownloadDialog.java:234)
        at org.openstreetmap.josm.gui.download.DownloadDialog.<init>(DownloadDialog.java:222)
        at org.openstreetmap.josm.gui.download.DownloadDialog.getInstance(DownloadDialog.java:66)
        at org.openstreetmap.josm.actions.DownloadAction.actionPerformed(DownloadAction.java:43)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2026)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2366)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:404)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:261)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:266)
        at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:297)
        at java.awt.Component.processMouseEvent(Component.java:6607)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3361)
        at java.awt.Component.processEvent(Component.java:6372)
        at java.awt.Container.processEvent(Container.java:2259)
        at java.awt.Component.dispatchEventImpl(Component.java:4991)
        at java.awt.Container.dispatchEventImpl(Container.java:2317)
        at java.awt.Component.dispatchEvent(Component.java:4823)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4906)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4543)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4484)
        at java.awt.Container.dispatchEventImpl(Container.java:2303)
        at java.awt.Window.dispatchEventImpl(Window.java:2759)
        at java.awt.Component.dispatchEvent(Component.java:4823)
        at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:761)
        at java.awt.EventQueue.access$500(EventQueue.java:97)
        at java.awt.EventQueue$3.run(EventQueue.java:712)
        at java.awt.EventQueue$3.run(EventQueue.java:706)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:77)
        at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87)
        at java.awt.EventQueue$4.run(EventQueue.java:734)
        at java.awt.EventQueue$4.run(EventQueue.java:732)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:77)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:731)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:192)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:117)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:106)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:102)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:94)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:83)



REGRESSION. Last worked in version 8u60

ADDITIONAL REGRESSION INFORMATION:
java version "1.8.0_51"
Java(TM) SE Runtime Environment (build 1.8.0_51-b16)
Java HotSpot(TM) 64-Bit Server VM (build 25.51-b03, mixed mode)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Call:

java.lang.management.ManagementFactory.getPlatformMBeanServer();


EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
No exception thrown
ACTUAL -
java.lang.NoClassDefFoundError: com/sun/management/internal/GarbageCollectorExtImpl
        at sun.management.MemoryImpl.getMemoryManagers0(Native Method)
        at sun.management.MemoryImpl.getMemoryManagers(MemoryImpl.java:98)
        at sun.management.ManagementFactoryHelper.getGarbageCollectorMXBeans(ManagementFactoryHelper.java:130)
        at java.lang.management.DefaultPlatformMBeanProvider$4.nameToMBeanMap(DefaultPlatformMBeanProvider.java:185)
        at java.lang.management.ManagementFactory.lambda$getPlatformMBeanServer$0(ManagementFactory.java:478)
        at java.util.stream.ReferencePipeline$7$1.accept(ReferencePipeline.java:269)
        at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:177)
        at java.util.HashMap$ValueSpliterator.forEachRemaining(HashMap.java:1664)
        at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482)
        at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
        at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
        at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
        at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
        at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:430)
        at java.lang.management.ManagementFactory.getPlatformMBeanServer(ManagementFactory.java:479)
        at org.apache.commons.jcs.engine.control.CompositeCacheManager.initialize(CompositeCacheManager.java:262)
        at org.apache.commons.jcs.engine.control.CompositeCacheManager.getUnconfiguredInstance(CompositeCacheManager.java:214)
        at org.openstreetmap.josm.data.cache.JCSCacheManager.initialize(JCSCacheManager.java:117)
        at org.openstreetmap.josm.data.cache.JCSCacheManager.getCache(JCSCacheManager.java:148)
        at org.openstreetmap.josm.gui.layer.AbstractCachedTileSourceLayer.getCache(AbstractCachedTileSourceLayer.java:122)
        at org.openstreetmap.josm.gui.layer.AbstractCachedTileSourceLayer.getTileLoaderFactory(AbstractCachedTileSourceLayer.java:113)
        at org.openstreetmap.josm.gui.bbox.SlippyMapBBoxChooser.<init>(SlippyMapBBoxChooser.java:143)
        at org.openstreetmap.josm.gui.download.SlippyMapChooser.<init>(SlippyMapChooser.java:34)
        at org.openstreetmap.josm.gui.download.DownloadDialog.buildMainPanel(DownloadDialog.java:122)
        at org.openstreetmap.josm.gui.download.DownloadDialog.<init>(DownloadDialog.java:234)
        at org.openstreetmap.josm.gui.download.DownloadDialog.<init>(DownloadDialog.java:222)
        at org.openstreetmap.josm.gui.download.DownloadDialog.getInstance(DownloadDialog.java:66)
        at org.openstreetmap.josm.actions.DownloadAction.actionPerformed(DownloadAction.java:43)
        at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2026)
        at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2366)
        at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:404)
        at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:261)
        at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:266)
        at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:297)
        at java.awt.Component.processMouseEvent(Component.java:6607)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3361)
        at java.awt.Component.processEvent(Component.java:6372)
        at java.awt.Container.processEvent(Container.java:2259)
        at java.awt.Component.dispatchEventImpl(Component.java:4991)
        at java.awt.Container.dispatchEventImpl(Container.java:2317)
        at java.awt.Component.dispatchEvent(Component.java:4823)
        at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4906)
        at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4543)
        at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4484)
        at java.awt.Container.dispatchEventImpl(Container.java:2303)
        at java.awt.Window.dispatchEventImpl(Window.java:2759)
        at java.awt.Component.dispatchEvent(Component.java:4823)
        at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:761)
        at java.awt.EventQueue.access$500(EventQueue.java:97)
        at java.awt.EventQueue$3.run(EventQueue.java:712)
        at java.awt.EventQueue$3.run(EventQueue.java:706)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:77)
        at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:87)
        at java.awt.EventQueue$4.run(EventQueue.java:734)
        at java.awt.EventQueue$4.run(EventQueue.java:732)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:77)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:731)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:192)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:117)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:106)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:102)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:94)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:83)

REPRODUCIBILITY :
This bug can be reproduced always.