When a public API in a sealed package try to create an inner anonymous class, AccessControlException is throw with a stack similar to following,
Exception in thread "Thread-13" java.security.AccessControlException: access denied ("java.lang.RuntimePermission" "accessClassInPackage.com.sun.deploy.uitoolkit.impl.fx")
at java.security.AccessControlContext.checkPermission(Unknown Source)
at java.security.AccessController.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPermission(Unknown Source)
at java.lang.SecurityManager.checkPackageAccess(Unknown Source)
at sun.plugin2.applet.SecurityManagerHelper.checkPackageAccessHelper(SecurityManagerHelper.java:248)
at sun.plugin2.applet.FXAppletSecurityManager.checkPackageAccess(FXAppletSecurityManager.java:93)
at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClass(Unknown Source)
at com.sun.deploy.net.DeployClassLoader.loadClass(DeployClassLoader.java:115)
at java.lang.ClassLoader.loadClass(Unknown Source)
at com.sun.deploy.uitoolkit.impl.fx.FXPluginToolkit$4.leaveBlockingMode(FXPluginToolkit.java:205)
at com.sun.deploy.uitoolkit.ToolkitStore$TaskThread.run(ToolkitStore.java:444)