The java.io regression tests can't be run in JPRT in samevm mode without excluding many tests. The reasons for the exclusion are many:

1. Many tests leave files open, which causes problems in subsequent tests (esp. on Windows)
2. A couple of tests uses Runtime.exec assuming the working directory is the test directory
3. At least one test assumes that it is loaded by the system class loader
4. At least one test uses the DOS attrib command to set the hidden attribute but doesn't restore it