Run applications

Run from the editor

If you are not going to pass any parameters to your program, and your program does not require any specific actions to be performed before start, you can run it right from the editor.

note

The class that you are going to execute must contain a main() method with a valid signature, for example: public static void main(String[] args).

• Click in the gutter near the class declaration and select Run.

  

1. Click in the gutter near the class declaration and select Modify Run Configuration.

   

2. Modify the run/debug configuration as needed. For example, if you need to run your program with arguments, add the arguments to the Program arguments field.

   To access additional parameters, click Modify options and select the required option from the menu.

   tip

   To quickly access the fields only using a keyboard, hold and use the shortcut according to the hints that appear.

   

3. Click OK to save the run configuration for later, or Run to save and run it right-away.

• On the toolbar of the Run tool window, click or press .

  

Stop a program

• In the Run tool window, click on the toolbar. Alternatively, press and select the process to stop.

  This performs a forceful termination of the program, meaning that the usual cleanup mechanisms at the operating system, virtual machine, and application levels may be bypassed, possibly preventing the execution of shutdown hooks, proper resource releasing, logging, and so on.

Terminate a program gracefully

• In the Run tool window, click on the toolbar.

  Unlike forceful termination, this terminates the program in a graceful way, the same as when it closes normally.

Pause the program output

• Right-click in the Run tool window and select Pause Output from the context menu. Use the same toggle to resume the program.

  

note

Only the output is suspended. Pausing the output does not affect the execution of the program.

• If an exception is thrown:

  • If the meaning of the exception is unclear, you can navigate to the exception class right from the stack trace and read the documentation for the exception. This may help you understand its cause. In some cases, this is enough to sort out the problem.

  • Attach the debugger and examine the program state that led to the failure. See Tutorial: Debug your first Java application for a quick introduction to IntelliJ IDEA debugger.

  • Run static analysis to see where incorrect values might be coming from.

• If a logic error is present, the debugger may save you a lot of time finding and fixing the cause. See Tutorial: Debug your first Java application for a quick introduction to IntelliJ IDEA debugger.

• If the problem is related to application performance, IntelliJ IDEA profiler will help you analyze the problem and assess how efficient your fix is.

• Go to Run | Show Running List. In the top-right corner of the editor, IntelliJ IDEA shows a list with all active applications.