Question

Like such Java code snippet:

public void func() throws XXXException {    // throw exception to outer body ------ (2)
    try {
        ......
    } catch(XXXException ex) {
        // handle exception ------ (1)
    }
}

In this condition, how you decide to choose (1) or (2)? Is there any principles in Java exception handling?

Answer 1

If the code that calls the method that throws the exception can properly deal with the exception then it should catch it. If it cannot deal with the exception then it should throw it up.

For instance, if “func” is low-level networking code it should probably throws the exception rather than catch it. The code that ultimatly catches it should display an error message to the user (or whatever else makes sense). If instead “func” is part of the GUI layer it probably would catch the exception and display an error message to the user (or whatever else makes sense).