Eclipse: Add Debug Statements to Code You Don't Own

One of the tricky aspects of this, however, is when dealing with a lot of code that you don't own, you can't easily go changing it to add print statements to debug. Sure, you can still debug that code with breakpoints, but if the code in question is complex (like my favorite pain-to-debug example: SAX parsers) breakpoints are sometimes not the right solution. Besides, some code (such as UI event code) may need to have errors reproduced without affecting the execution (such as typing 3 characters, right mouse clicking, and hitting tab all without losing focus to reproduce a null pointer exception). In those cases, it would be nice to get in there, and throw some print statements in to see when code is hit (and potentially to print out any variable values at the time of the breakpoint). This can be done by 'cheating the system' in Eclipse a little bit, and using conditional breakpoints.

Conditional breakpoints are a handy feature in Eclipse that allow you to supply a condition contextually relative to the code being executed so that the breakpoint only stops when that condition is met. They can be really useful, and in a lot of cases they can make debugging a lot less tedious. They don't really help with what I am describing here exactly (at least not directly), but it is important to understand them. To create a conditional breakpoint for this code:

public void someMethod(String argument) {   String a = getSomeValue();   String b = getSomeOtherValue(); // conditional breakpoint on this line  }  

... you add the breakpoint in your editor by either right clicking and adding it, or double clicking in the breakpoint gutter. Once installed, right click, select Properties for the breakpoint, and then enable a condition:

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