How to realize the key combination in Java to monitor events? Such as press Alt + left mouse button!

Personal problems in:
1.
Listen for an event the keyboard Alt key
2.
Press the Alt key Boolean value of true
Loosen the Alt key Boolean falet
(Boolean value is used to control the right mouse button to judge whether the response)
3.
Key combination to realize the Alt + left mouse button


Results failed QWQ
Problem: after clicking on the button, button appears, keyboard press the Alt key is not more change!!!!!! Bosses for directions!