Java: Exception Handling

Question

Is there any reason for not converting the following code

try {
    // Do something
} catch (XException e) {
    e.printStackTrace();
} catch (YException e) {
    e.printStackTrace();
} catch (ZException e) {
    e.printStackTrace();
}

to this:

try {
    // Do something
} catch (Exception e) {
    e.printStackTrace();
}

I know the 2nd one catches all kinds of Exceptions, and I don't mind that. And let's say I want to handle all exceptions in the same way. Is the performance difference considerable?

Answer 1

The Java try/catch mechanism has been so highly tuned in successive JVM's that their performance is never something you should be explicitely worried about. Rather, you should be coding those blocks according to whether you need to handle the caught error scenarios in different ways. In your example you are just printing a stack trace so it is not beneficial to catch the specific errors - but your use case will actually determine wether you should be rolling up or down for these try/catch blocks.

Answer 2

This separation is only because you would be able to perform different task for different exceptions. Like if you receive parse exception and you get IO exception so you would know exactly what to do with each exception.

In newer version this blocks has been minimized with multiple exception in on block which will help the coder and increase the readability. e.g.

try {
    // Do something
} catch (XException | YException | ZException e) {
    e.printStackTrace();
}

Answer 3

I wouldn't worry about performance at the moment (unless you know it's a real issue).

You may want to convert for readability (if the same action is performed for each type of excpeption), but don't forget that catching Exception will catch lots of other stuff besides XException, YException, ZException. Is there a useful base class for those, and can you catch that instead ?