Compiling and Running Programs
in JBuilder

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Compiling

The simplest method is to simply "run" your program by clicking either of the two green VCR-like "play" button .   The plain "run" button will compile any files that have changed and then run the program.  The "run" button with the arrow and box will compile the project as well, but will run the program using the debugger.

If you want to manually compile your project or individual files, under the "Project" menu, there are a number of choices:

  1. Make Project : Compiles only those files in the porject that have changed since the last time the project was compiled.
  2. Rebuild Project :   Recompiles all the files in the project.
  3. Make "XXX.java":  Compiles just the indicated file if it has changed.
  4. Rebuild "XXX.java": Compiles the indicated file.

If you are concerned about problems in your project, "Rebuild Project" is your safest choice.

Compilation Errors

If an error is encountered during comilation, error messages will  appear in the message window near the bottom of the screen.  Double clicking on the error message will take you to the offending line in the code.  

As always, correct the first few errors first and try recompiling.   Many of the later errors result from the  first few.

Running a Program

To run your program, just click on the green VCR-like "play" button on the task bar.

If JB cannot find the "main" method, as may be the case if that file was written externally to JB .  To tell JB which file has the "main" method, select "Project/Options" from the main menu.   On the "Projects" tab, find and fill in the "Main Class" field with the name of the appropriate file (class) with no file extension.