(286/286) 1853 - XML plugin crashes on JDK9

With recent early access releases of [JDK9](https://jdk9.java.net/download/) (e.g. 9-ea+113), the XML plugin crashes on plugin startup:
~~~~
java.lang.IllegalStateException: Already connected
at java.net.URLConnection.checkConnected(java.base@9-ea/URLConnection.java:1816)
at java.net.URLConnection.setUseCaches(java.base@9-ea/URLConnection.java:993)
at java.util.ServiceLoader.parse(java.base@9-ea/ServiceLoader.java:454)
...
at javax.xml.parsers.FactoryFinder.findServiceProvider(java.xml@9-ea/FactoryFinder.java:289)
...
at org.apache.xml.resolver.Catalog.setupReaders(Catalog.java:399)
at xml.Resolver.load(Resolver.java:270)
...
at xml.XmlPlugin.start(XmlPlugin.java:54)
...
~~~~

Submitted	will69 - 2016-04-11 10:28:24.912000	Assigned	kerik-sf
Priority	5	Labels	JDK9 XML
Status	open	Group	None
Resolution	None

Comments

2016-04-11 10:42:56.460000 will69	XML plugin startup initializes the internal jEdit XML resolver. That in turn triggers the URL stream handler for "jeditresource:" URLs. And that returns an already connected URLConnection in its [openConnection() method](https://sourceforge.net/p/jedit/svn/HEAD/tree/jEdit/trunk/org/gjt/sp/jedit/proto/jeditresource/Handler.java#l46). The subsequent call to [setUseCaches()](http://hg.openjdk.java.net/jdk9/dev/jdk/file/550572253bd8/src/java.base/share/classes/java/net/URLConnection.java#l993) on that URLConnection throws the [IllegalStateException](http://hg.openjdk.java.net/jdk9/dev/jdk/file/550572253bd8/src/java.base/share/classes/java/net/URLConnection.java#l1816) when it finds that the URLConnection is already connected. To solve this problem, please erase [line 46](https://sourceforge.net/p/jedit/svn/HEAD/tree/jEdit/trunk/org/gjt/sp/jedit/proto/jeditresource/Handler.java#l46) (<tt>c.connect()</tt>) in the "jeditresource:" URL stream handler. The handler must not return a connected URLConnection. See also [Bug #3912](https://sourceforge.net/p/jedit/bugs/3912/).
2016-04-25 10:41:45.457000 will69	Just to be perfectly clear: This is a bug and it has been for 17 years. The only thing this has to do with Java 9 is that Java 9 tells you so. Would some kind soul please take the offending line out?

2016-04-11 10:42:56.460000
will69

XML plugin startup initializes the internal jEdit XML resolver. That in turn triggers the URL stream handler for "jeditresource:" URLs. And that returns an already connected URLConnection in its [openConnection() method](https://sourceforge.net/p/jedit/svn/HEAD/tree/jEdit/trunk/org/gjt/sp/jedit/proto/jeditresource/Handler.java#l46). The subsequent call to [setUseCaches()](http://hg.openjdk.java.net/jdk9/dev/jdk/file/550572253bd8/src/java.base/share/classes/java/net/URLConnection.java#l993) on that URLConnection throws the [IllegalStateException](http://hg.openjdk.java.net/jdk9/dev/jdk/file/550572253bd8/src/java.base/share/classes/java/net/URLConnection.java#l1816) when it finds that the URLConnection is already connected.

To solve this problem, please erase [line 46](https://sourceforge.net/p/jedit/svn/HEAD/tree/jEdit/trunk/org/gjt/sp/jedit/proto/jeditresource/Handler.java#l46) (<tt>c.connect()</tt>) in the "jeditresource:" URL stream handler. The handler must not return a *connected* URLConnection.

See also [Bug #3912](https://sourceforge.net/p/jedit/bugs/3912/).

2016-04-25 10:41:45.457000
will69

Just to be perfectly clear: This is a bug and it has been for 17 years. The only thing this has to do with Java 9 is that Java 9 tells you so. Would some kind soul please take the offending line out?