A Simple Mistake of Using Java Exception

Recently I ran into the following code in a legacy system:

try {
...
} except (Exception e) {
System.out.println(e.getStackElement());
}


While it may look innocent, it’s actually dangerous. In case of an exception, the system prints the String representation of e.getStackElement(), which actually is of type StackElement[]. Since it is an array, its String representation is only the address of the array, instead of the content of the array. Since the output is a one-liner, it does not catch one’s eye in the log, and it may take some time (and really took mine) for the debugger to find the exception.

I have no idea why the original programmer come up with the idea of using getStackElement(). Maybe he thought println(e.getStackElement()) were the same as e.printStackElement().

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Tags: exception, java, programming