1. Add traces around variables

2. Add traces around this object, toString() would print object state

    System.out.println(" State : " + this);

3. Put a separate main method in each class. Inside it, you can put a unit test stub that lets you test the class in isolation

4. Put the stack trace for an exception object

    e.printStackTrace();

    You don't even need to catch an exception to generate a stack trace.

    Thread.dumpStack();

5. Capture System.err and System.out to a file

    java MyProgram 2>&1 error.txt

6. Run java with -verbose flag

7. Concurrency Issues

    a. Thread Interference Errors (Race Conditions) - Thread interference errors can be avoided by synchronizing access to shared variables.

    b. Memory Consistency Errors (Compiler\Processor optimization) - when different threads have inconsistent views of the same data. - use volatile keyword