org.netbeans.api.db.explorer.DatabaseException: java.util.ConcurrentModificationException
        at org.netbeans.modules.db.explorer.infos.RootNodeInfo.initChildren(RootNodeInfo.java:170)
        at org.netbeans.modules.db.explorer.infos.DatabaseNodeInfo.loadChildren(DatabaseNodeInfo.java:710)
        at org.netbeans.modules.db.explorer.infos.DatabaseNodeInfo.getChildren(DatabaseNodeInfo.java:698)
        at org.netbeans.modules.db.explorer.infos.RootNodeInfo.addConnection(RootNodeInfo.java:235)
        at org.netbeans.api.db.explorer.ConnectionManager.addConnection(ConnectionManager.java:145)
        at org.netbeans.modules.derby.api.DerbyDatabases.registerDatabase(DerbyDatabases.java:366)
        at org.netbeans.modules.derby.api.DerbyDatabases.createSampleDatabase(DerbyDatabases.java:282)
        at org.netbeans.modules.derby.Installer$RegisterJDKDerby.registerSampleDatabase(Installer.java:108)
        at org.netbeans.modules.derby.Installer$RegisterJDKDerby.run(Installer.java:87)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:572)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:997)
java.util.ConcurrentModificationException
        at java.util.AbstractList$Itr.checkForComodification(AbstractList.java:372)
        at java.util.AbstractList$Itr.next(AbstractList.java:343)
        at org.netbeans.modules.db.mysql.impl.InstallationManager.detectInstallation(InstallationManager.java:118)
        at org.netbeans.modules.db.mysql.impl.ServerNodeProvider.findAndRegisterInstallation(ServerNodeProvider.java:115)
        at org.netbeans.modules.db.mysql.impl.ServerNodeProvider.findAndRegisterMySQL(ServerNodeProvider.java:104)
        at org.netbeans.modules.db.mysql.impl.ServerNodeProvider.getNodes(ServerNodeProvider.java:146)
        at org.netbeans.modules.dbapi.DbNodeLoaderImpl.getAllNodes(DbNodeLoaderImpl.java:82)
        at org.netbeans.modules.db.explorer.infos.RootNodeInfo.getRegisteredNodeInfos(RootNodeInfo.java:187)
        at org.netbeans.modules.db.explorer.infos.RootNodeInfo.initChildren(RootNodeInfo.java:149)
        at org.netbeans.modules.db.explorer.infos.DatabaseNodeInfo.loadChildren(DatabaseNodeInfo.java:710)
        at org.netbeans.modules.db.explorer.infos.DatabaseNodeInfo.getChildren(DatabaseNodeInfo.java:698)
        at org.netbeans.modules.db.explorer.infos.RootNodeInfo.addConnection(RootNodeInfo.java:235)
        at org.netbeans.api.db.explorer.ConnectionManager.addConnection(ConnectionManager.java:145)
        at org.netbeans.modules.derby.api.DerbyDatabases.registerDatabase(DerbyDatabases.java:366)
        at org.netbeans.modules.derby.api.DerbyDatabases.createSampleDatabase(DerbyDatabases.java:282)
        at org.netbeans.modules.derby.Installer$RegisterJDKDerby.registerSampleDatabase(Installer.java:108)
        at org.netbeans.modules.derby.Installer$RegisterJDKDerby.run(Installer.java:87)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:572)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:997)