Otherwise a normal streamhandler lookup is made and if javassist is used early on server startup protses this can lead to a deadlock on rare cases on WebSpheare.
For example. A new StreamHandlerFactory is registered but not jet fully initialized. Now javassist is used at the same time but form another thread and it will be the first one to invoke the new StreamHandlerFactory and now it can deadlock with the other thread:
Snipets from my deadlock:
3XMTHREADINFO "main" J9VMThread:0x000000000175EC00, omrthread_t:0x00007F4120008100, java/lang/Thread:0x00000000624290B8, state:B, prio=5
3XMTHREADBLOCK Blocked on: org/osgi/util/tracker/ServiceTracker$Tracked@0x00000000627F0A90 Owned by: "other-thread" (J9VMThread:0x0000000001B26300, java/lang/Thread:0x00000000629F1458)
3XMHEAPALLOC Heap bytes allocated since last GC cycle=0 (0x0)
3XMTHREADINFO3 Java callstack:
4XESTACKTRACE at org/osgi/util/tracker/ServiceTracker.getServiceReferences(ServiceTracker.java:525)
4XESTACKTRACE at org/eclipse/osgi/framework/internal/protocol/StreamHandlerFactory.createInternalURLStreamHandler(StreamHandlerFactory.java:162)
4XESTACKTRACE at org/eclipse/osgi/framework/internal/protocol/StreamHandlerFactory.createURLStreamHandler(StreamHandlerFactory.java:118)
4XESTACKTRACE at java/net/URL.getURLStreamHandler(URL.java:1154)
4XESTACKTRACE at java/net/URL.<init>(URL.java:611(Compiled Code))
4XESTACKTRACE at java/net/URL.<init>(URL.java:502(Compiled Code))
4XESTACKTRACE at java/net/URL.<init>(URL.java:451)
4XESTACKTRACE at javassist/ByteArrayClassPath.find(JRebel:92)
...
4XESTACKTRACE at java/lang/ClassLoader.loadClassHelper(ClassLoader.java:924(Compiled Code))
5XESTACKTRACE (entered lock: org/eclipse/core/launcher/Main$StartupClassLoader@0x0000000062F3AA88, entry count: 1)
3XMTHREADINFO "other-thread" J9VMThread:0x0000000001B26300, omrthread_t:0x00007F4120A5D060, java/lang/Thread:0x00000000629F1458, state:B, prio=5
3XMTHREADBLOCK Blocked on: org/eclipse/core/launcher/Main$StartupClassLoader@0x0000000062F3AA88 Owned by: "main" (J9VMThread:0x000000000175EC00, java/lang/Thread:0x00000000624290B8)
3XMHEAPALLOC Heap bytes allocated since last GC cycle=0 (0x0)
3XMTHREADINFO3 Java callstack:
4XESTACKTRACE at org/osgi/util/tracker/AbstractTracked.size(AbstractTracked.java:356)
4XESTACKTRACE at org/osgi/util/tracker/ServiceTracker.getServiceReferences(ServiceTracker.java:526)
5XESTACKTRACE (entered lock: org/osgi/util/tracker/ServiceTracker$Tracked@0x00000000627F0A90, entry count: 1)
4XESTACKTRACE at org/eclipse/osgi/framework/internal/protocol/StreamHandlerFactory.createInternalURLStreamHandler(StreamHandlerFactory.java:162)
4XESTACKTRACE at org/eclipse/osgi/framework/internal/protocol/StreamHandlerFactory.createURLStreamHandler(StreamHandlerFactory.java:118)
4XESTACKTRACE at java/net/URL.getURLStreamHandler(URL.java:1154)
4XESTACKTRACE at java/net/URL.<init>(URL.java:611(Compiled Code))
4XESTACKTRACE at java/net/URL.<init>(URL.java:502(Compiled Code))
4XESTACKTRACE at java/net/URL.<init>(URL.java:451)
4XESTACKTRACE at java/net/URI.toURL(URI.java:1100)
4XESTACKTRACE at com/ibm/jsse2/av.a(av.java:92)
4XESTACKTRACE at com/ibm/jsse2/av.engineInit(av.java:7)
4XESTACKTRACE at javax/net/ssl/TrustManagerFactory.init(TrustManagerFactory.java:25)