To suspend executing threads:
In the Debug view, select a running thread.
Click the Suspend button in the Debug view toolbar. The thread suspends its execution. The current call stack for the thread is displayed, and the current line of execution is highlighted in the editor in the Debug perspective.
When a thread is suspended and the cursor is placed over a variable in the Java editor, the value of that variable is displayed as hover help.
When a thread suspends, the top stack frame of the thread is automatically selected. When a stack frame is selected, the visible variables in that stack frame are displayed in the Variables view. Variables can be examined by expanding those variables that have children.
Debugger
Java editor
Java perspectives
Catching Java exceptions
Evaluating
expressions
Resuming the execution of suspended threads
Stepping through
the execution of a program