The Output window is a multi-tabbed window that displays messages from the IDE. This window is displayed automatically when you encounter compilation errors, debug your program, generate Javadoc documentation, and so on. You can also open this window by choosing Window > Output (Ctrl-4).
One function of the Output window is to notify you of errors found while compiling your program. The error message is displayed in blue underlined text and is linked to the line in the source code that caused the error. The Output window also provides links to errors found when running Ant build scripts and when checking and validating XML documents.
If the file that contains the error is open, the Source Editor jumps to the line containing each error as you move the insertion point into the error in the Source Editor. You can also use the F12 and Shift-F12 keyboard shortcuts to move to the next and previous error in the file.
When you run a program that requires user input, a new tab appears in the Output window. This tab includes a cursor. You can enter information in the Output window as you would on a command line.