For JCK test suite test tree initialization takes ~7-10 sec. If user is fast enough, and tries to load custom .jti configuration while test tree cache isn't ready, user gets IAE.

This can be reproduced if .jti file contains set of tests selected, e.g:

jck.tests.tests=api/java_net/URL


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D:\test4\JCK-runtime-8\lib>java -jar javatest.jar -newdesktop
Exception in thread "Test Tree Cache Worker" java.lang.IllegalArgumentException: Last path component must be non-null
        at javax.swing.tree.TreePath.<init>(Unknown Source)
        at javax.swing.event.TreeModelEvent.<init>(Unknown Source)
        at com.sun.javatest.exec.TestTreeModel$CacheWorker.finishJob(TestTreeModel.java:1399)
        at com.sun.javatest.exec.TestTreeModel$CacheWorker.run(TestTreeModel.java:1198)
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