FAQ How do I set a conditional breakpoint?
First, set a breakpoint at a given location. Then, use the context menu on the breakpoint in the left editor margin or in the Breakpoints view in the Debug perspective, and select the breakpoints properties. In the dialog box, check Enable Condition, and enter an arbitrary Java condition, such as list.size()==0. Now, each time the breakpoint is reached, the expression is evaluated in the context of the breakpoint execution, and the breakpoint is either ignored or honored, depending on the outcome of the expression.
Conditions can also be expressed in terms of other breakpoint attributes, such as hit count.