When running JCK runtime tests on 1.3.1_12 build 1 using the -Xcheck:jni flag 5 tests fail. These are:
api/javax_swing/JPasswordField/descriptions.html#setgetXXX
api/javax_swing/text/DefaultEditorKit/CopyAction/index.html#SubCtors
api/javax_swing/text/DefaultEditorKit/CutAction/index.html#SubCtors
api/javax_swing/text/DefaultEditorKit/PasteAction/index.html#SubCtors
api/javax_swing/text/JTextComponent/index.html#copy_paste

The error that comes up for these tests are:

FATAL ERROR in native method: Bad global or local ref passed to JNI
at sun.awt.motif.X11Selection.pGetTransferTargets(Native Method)
at sun.awt.motif.SelectionThread.run(X11Selection.java:302)

I ran the tests on a Solaris 9/x86 update 5.