Minor Description
The test DerbyNetAutoStart uses RandomAccessFile.readLine() on derby.log to find an occurrence of a String[] to decide whether the tests passes or not.
This mechanism assumes that derby.log is in Unicode-compatible encoding, which may not be true.
Also, readLine() documentation indicates that it does not support the 'full Unicode range', so may not be the best choice.
And indeed, the test fails on zOS, even though the string looked for is present in derby.log.