How to track value of a variable in Eclipse Java Debugger

Question

I would like to track the value of a boolean (not Boolean) variable in the Eclipse debugger.

I need to know when it does change and, for this, i need to track it's value through all the execution; not only when it is in scope.

More particularly: I have a class (let's call it myClass) with a boolean member variable called isAvailable. My program instantiate 4 or 5 myClass objects. I am expecting that at the end of the execution the isAvailable value of all of my objects is set to true. Contrarily to my excpectation one of myClass objects has isAvailable set to false. I need to know which (in a lot of) methods is setting isAvailable to false.

Answer 1

You can set a watchpoint on the member field. A watchpoint is like a breakpoint that suspends execution when the field is either accessed or modified (you can configure which conditions you want to stop at). See http://www.vogella.com/articles/EclipseDebugging/article.html#advanced_watchpoint

Answer 2

Do you have access to the code the class is in?

Instead of using the variable use setters and getters to access it, then just put a break point on the setter.

IF you just need to know when it changes put a conditional break point and have the expression be something like:

available != this.available

Assuming your setter is of the following format:

public void setAvailable(boolean available){
    this.available = available;
}

You can get a conditional break point by right clicking on the break point symbol once you've set a break point.

Here is an FAQ about conditional break points: http://wiki.eclipse.org/FAQ_How_do_I_set_a_conditional_breakpoint%3F