NetBeans: The Definitive Guide

Chapter 4. Debugging

Debugger Types

Real programmers know that watching their applications run smoothly isn’t nearly as much fun as just getting them to run in the first place. The best part is seeing what’s going on under the hood. Don’t you just love to watch the threads weaving around, and the values in one variable affecting another like a chain of dominos falling over? Well, the people at NetBeans understand, so they created some great debugging features. In the event that you make a programming error and can’t immediately see what’s wrong, you can use these debugging features to find out what’s really going on. But I’m sure you’re more careful than that, so just think of debugging as a fun diversion from writing code. Here are some of the ways you can play with the inner workings of your programs while they’re running:

• Set breakpoints

• Watch values change for variables and expressions

• Examine and modify variable values

• Step through code, line by line

• Examine running threads, classes, and the callstack

• Run several debugging sessions at the same time

Actually, the same user interface supports a choice of backend debugging facilities. The Java Platform Debugger Architecture (JPDA) is the default. Be sure to specify the right debugger type for the object to be debugged; these types are delineated in Table 4-1.

Table 4-1. Debugger types that come with NetBeans 3.3

Debugger type	Remarks	Where to use it
Default	Based on JPDA	Use with ordinary Java applications
Applet	Based on ...