In the source editor, add breakpoints to your code so you can pause at known points while debugging and inspect the values of variables.
Add a breakpoint: Click the gutter next to the line where you want execution to pause.
Move a breakpoint: Click a breakpoint and drag it to a new location in the gutter.
Set breakpoint options: Control-click the breakpoint, choose Edit Breakpoint from the pop-up menu, then adjust the breakpoint actions and breakpoint options.
Disable or enable a breakpoint: Click the breakpoint icon in the gutter. A disabled breakpoint appears lighter in color and remains in your project, but is ignored during debugging.
Deactivate all breakpoints: Click the breakpoint icon in the debug area or choose Debug > Deactivate Breakpoints. Breakpoints appear gray in color when deactivated, and are ignored during debugging.
Activate all breakpoints: Click the breakpoint icon in the debug bar or choose Debug > Activate Breakpoints.
Delete a breakpoint: Control-click the breakpoint, then choose Delete Breakpoint from the pop-up menu, or drag the breakpoint out of the gutter.
Tip: You can use the Breakpoint navigator to further manage all of the breakpoints in your project.
When you build and run your app, the debug area automatically opens and the debugger stops the app at the breakpoint you specified.