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Language: Java
Expertise: All

May 26, 1999

One of the most frustrating experiences when running a Java program is an empty line where you expect information about a thrown exception. The programmer probably meant to catch the exception but did nothing with it. As a result, when the exception is thrown at run time, there is no way to indicate to the user that it was thrown, which leads to erroneous results. For example, consider a method called method1 that throws an exception.

 
1. private void method1 () throws Exception {
2.   // Do stuff
3.   throw new Exception();
4. }

Now consider this code:

 
1.     System.out.println("Start");
2. 	  
3.     try {
4.       method1();
5.     }
6.     catch (Exception e) {
7.       // EMPTY EXCEPTION HANDLER
8.     }
9.     System.out.println("End OK");

You catch the exception on Line 6. However, the program does nothing with the exception. The result is that at run time, there is no trace of the exception; it becomes nonexistent. The output of the code excerpt is:

 
Start
End OK

Therefore, you should avoid empty exception handlers as good programming practice.