This is a corresponding Sun bug ID for oracle bug: 10313631
https://bug.oraclecorp.com/pls/bug/webbug_print.show?c_rptno=10313631

WLS team have reported a deadlock situation with our classloader. Analysis of issue reported in bug.oraclecorp. Copy/paste of issue is : 

*** KRCHAKR  11/18/10 10:08 am ***
A remote call (RMI) from Weblogic client resulted in the following deadlock
in VM as shown in bugs -

1. 10274213
2. 9381468

Here the code (java.lang.ClassLoader) that causes the issue -

 protected Package getPackage(String name) {
    synchronized (packages) {
        Package pkg = (Package)packages.get(name);
        if (pkg == null) {
        if (parent != null) {
            pkg = parent.getPackage(name);
        } else {
            pkg = Package.getSystemPackage(name); - This Static call goes to
create a new URL for a system code source that in turn loads a protocol
handler class for "file" through ClassLoader.loadClass() thus resulting in
the deadlock.
        }
        if (pkg != null) {
            packages.put(name, pkg);
        }
        }
        return pkg;
    }
    }

The call finally goes into Package.defineSystemPackage().  The call then
steps in ParseUtil.fileToEncodedURL(). In this method, the VM has to create a
new URL(). In the URL() constructor, if the handler for "file" protocol is
null(), there is a call to getURLStreamHandler(). This method looks at the
factory and if it does not find the handler does the following -

           try {
                 cls = Class.forName(clsName);
            } catch (ClassNotFoundException e) {
            ClassLoader cl = ClassLoader.getSystemClassLoader();
                if (cl != null) {
                    cls = cl.loadClass(clsName);
               }
            }
        
If the context classloader is not the system classloader (which it is not),
it will fall back in <systemclassloader>.loadClass() to load the protocol
handler for the "file" protocol. loadClass() will go back into the
ClassLoader.getPackage() causing the deadlock.

*** KRCHAKR 11/18/10 10:10 am ***
This is a HOTSPOT bug. Please re-assign to HOTSpot team.
*** KRCHAKR 11/18/10 10:15 am ***

One early thought is to force the loading of the file URLStreamHandler early in load process before another calling thread places a lock on the getPackage call. Comments from classloader experts are welcome here.