General Java Questions IV

 Q: More about Robot! I met with a problem in using class Robot.mousePress...

The compiling process is successful. But when I run it, I receive

"IllegalArgumentException:

Invalid combination of button flags". I don t quit understand this information. Part of

my code is as following:

Robot rMouse=new Robot();

int button=1;

rMouse.mousePress(button);

rMouse.mouseRelease(button);

I am really confused. Will you please give me some advice? Thank you in advance!

Answer: You are not using a valid value for the argument to the mousePress() and

mouseRelease() methods. If you check the API documentation, you ll find the valid

values are a combination of one or more of the following constants:

InputEvent.BUTTON1_MASK

InputEvent.BUTTON2_MASK

InputEvent.BUTTON3_MASK

plus others which represent the Ctrl, Alt, and Shift keys. To press the left 

mouse button, you want to use:

rMouse.mousePress(InputEvent.BUTTON1_MASK);

Lee Weiner

 Q: In what situation an exception has to be caught otherwise the compiler will

complain?

e.g. IOException does NOT have to be explicitly caught, however, SQLException

has to be caught otherwise VisalAge will not compile the program.

Answer: The only unchecked exceptions in Java are RuntimeException and its

subclasses. This includes such familiar classes as NullPointerException,

ClassCastException, and IndexOutOfBoundsException.

IOException is not one of these, and *does* have to be explicitly caught or thrown

jeff_robertson

 Q: Is it possible to use switch with range of values?

Ex:

switch (iBegins){

   case 2 to 10:

}

Answer: 

not exactly like this but:

switch (iBegins){

   case 2:

   case 3:

   case 4:

   case 5:

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