(284/308) 1874 - XML plugin exception with Java 9-ea+157

There was also this exception:

java.lang.IllegalStateException: Already connected
at java.base/java.net.URLConnection.checkConnected(Unknown Source)
at java.base/java.net.URLConnection.setUseCaches(Unknown Source)
at java.base/java.util.ServiceLoader$LazyClassPathLookupIterator.parse(Unknown Source)
at java.base/java.util.ServiceLoader$LazyClassPathLookupIterator.hasNextService(Unknown Source)
at java.base/java.util.ServiceLoader$LazyClassPathLookupIterator.hasNext(Unknown Source)
at java.base/java.util.ServiceLoader$1.hasNext(Unknown Source)
at java.base/java.util.ServiceLoader$2.hasNext(Unknown Source)
at java.xml/javax.xml.parsers.FactoryFinder$1.run(Unknown Source)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.xml/javax.xml.parsers.FactoryFinder.findServiceProvider(Unknown Source)
at java.xml/javax.xml.parsers.FactoryFinder.find(Unknown Source)
at java.xml/javax.xml.parsers.SAXParserFactory.newInstance(Unknown Source)
at org.apache.xml.resolver.Catalog.setupReaders(Catalog.java:399)
at xml.Resolver.load(Resolver.java:270)
at xml.Resolver.instance(Resolver.java:205)
at xml.XmlPlugin.start(XmlPlugin.java:54)
at org.gjt.sp.jedit.PluginJAR.startPlugin(PluginJAR.java:1740)
at org.gjt.sp.jedit.PluginJAR.activatePlugin(PluginJAR.java:951)
at org.gjt.sp.jedit.JARClassLoader._loadClass(JARClassLoader.java:393)
at org.gjt.sp.jedit.JARClassLoader.loadClass(JARClassLoader.java:109)
at java.base/java.lang.ClassLoader.loadClass(Unknown Source)
at org.gjt.sp.jedit.bsh.classpath.ClassManagerImpl.classForName(ClassManagerImpl.java:203)
at org.gjt.sp.jedit.bsh.NameSpace.classForName(NameSpace.java:1318)
at org.gjt.sp.jedit.bsh.NameSpace.getClassImpl(NameSpace.java:1218)
at org.gjt.sp.jedit.bsh.NameSpace.getClass(NameSpace.java:1159)
at org.gjt.sp.jedit.bsh.Name.consumeNextObjectField(Name.java:298)
at org.gjt.sp.jedit.bsh.Name.toObject(Name.java:199)
at org.gjt.sp.jedit.bsh.BSHAmbiguousName.toObject(BSHAmbiguousName.java:60)
at org.gjt.sp.jedit.bsh.BSHAllocationExpression.objectAllocation(BSHAllocationExpression.java:86)
at org.gjt.sp.jedit.bsh.BSHAllocationExpression.eval(BSHAllocationExpression.java:62)
at org.gjt.sp.jedit.bsh.BSHPrimaryExpression.eval(BSHPrimaryExpression.java:102)
at org.gjt.sp.jedit.bsh.BSHPrimaryExpression.eval(BSHPrimaryExpression.java:47)
at org.gjt.sp.jedit.bsh.Interpreter.eval(Interpreter.java:644)
at org.gjt.sp.jedit.bsh.Interpreter.eval(Interpreter.java:738)
at org.gjt.sp.jedit.bsh.Interpreter.eval(Interpreter.java:727)
at org.gjt.sp.jedit.BeanShellFacade._eval(BeanShellFacade.java:153)
at org.gjt.sp.jedit.BeanShellFacade.eval(BeanShellFacade.java:117)
at org.gjt.sp.jedit.BeanShell.eval(BeanShell.java:382)
at org.gjt.sp.jedit.ServiceManager$Descriptor.getInstance(ServiceManager.java:344)
at org.gjt.sp.jedit.ServiceManager.getService(ServiceManager.java:270)
at sidekick.SideKickPlugin.getParser(SideKickPlugin.java:237)
at sidekick.SideKickPlugin.getParserForBuffer(SideKickPlugin.java:293)
at sidekick.SideKick.parse(SideKick.java:166)
at sidekick.SideKickPlugin.initView(SideKickPlugin.java:381)
at sidekick.SideKickPlugin.handleViewUpdate(SideKickPlugin.java:142)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at org.gjt.sp.jedit.EditBus.dispatch(EditBus.java:242)
at org.gjt.sp.jedit.EditBus.sendImpl(EditBus.java:281)
at org.gjt.sp.jedit.EditBus.access$200(EditBus.java:87)
at org.gjt.sp.jedit.EditBus$SendMessage.run(EditBus.java:461)
at org.gjt.sp.jedit.EditBus.send(EditBus.java:206)
at org.gjt.sp.jedit.jEdit.newView(jEdit.java:2578)
at org.gjt.sp.jedit.PerspectiveManager$PerspectiveHandler.endElement(PerspectiveManager.java:363)
at org.apache.xerces.parsers.AbstractSAXParser.endElement(Unknown Source)
at org.apache.xerces.impl.dtd.XMLNSDTDValidator.endNamespaceScope(Unknown Source)
at org.apache.xerces.impl.dtd.XMLDTDValidator.handleEndElement(Unknown Source)
at org.apache.xerces.impl.dtd.XMLDTDValidator.endElement(Unknown Source)
at org.apache.xerces.impl.XMLNSDocumentScannerImpl.scanEndElement(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl$FragmentContentDispatcher.dispatch(Unknown Source)
at org.apache.xerces.impl.XMLDocumentFragmentScannerImpl.scanDocument(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XML11Configuration.parse(Unknown Source)
at org.apache.xerces.parsers.XMLParser.parse(Unknown Source)
at org.apache.xerces.parsers.AbstractSAXParser.parse(Unknown Source)
at org.gjt.sp.util.XMLUtilities.parseXML(XMLUtilities.java:140)
at org.gjt.sp.jedit.SettingsXML.load(SettingsXML.java:155)
at org.gjt.sp.jedit.PerspectiveManager.loadPerspective(PerspectiveManager.java:107)
at org.gjt.sp.jedit.jEdit$8.run(jEdit.java:4187)
at java.desktop/java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.desktop/java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.desktop/java.awt.EventQueue.access$500(Unknown Source)
at java.desktop/java.awt.EventQueue$3.run(Unknown Source)
at java.desktop/java.awt.EventQueue$3.run(Unknown Source)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.desktop/java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.desktop/java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.desktop/java.awt.EventDispatchThread.run(Unknown Source)

- **status**: open --> pending
- **assigned_to**: Eric Le Lay
- **Group**: -->

The IllegalStateException has already been reported in [plugin-bugs:#1853] and fixed in jEdit core in [r24374]. You can verify that it's fixed by running a nightly jEdit build.
The ClassNotFoundException may or may not be caused by it.