jtreg 2.1.6 fails for *.java but works on directory name

On current builds of 1.4.2 (b16) and 1.5 (b2), I've obversed jtreg to fail on linux when running the BigInteger regression tests if the tests are specified as "*.java"; strangely, everything works fine if the tests are specified as ".". Run individually, the tests also all pass. Somehow, the file globbing seems to be involved. Sample failing stack trace:

TEST: java/math/BigInteger/ModPow.java
java.lang.StringIndexOutOfBoundsException: String index out of range: -1
        at java.lang.String.substring(String.java:1438)
        at com.sun.javatest.regtest.Main$RegressionObserver.getTestJDK(Main.java:580)
        at com.sun.javatest.regtest.Main$RegressionObserver.printOutput(Main.java:433)
        at com.sun.javatest.regtest.Main$RegressionObserver.finished(Main.java:403)
        at javasoft.sqe.javatest.TestRunner$Notifier.finished(TestRunner.java:282)
        at javasoft.sqe.javatest.TestRunner$Worker.runTest(TestRunner.java:257)
        at javasoft.sqe.javatest.TestRunner$Worker.run(TestRunner.java:210)