Learning Java

BeanShell Commands

BeanShell comes with a number of useful built-in commands (methods). These commands are implemented as BeanShell scripts, and are supplied in the bsh JAR file. You can make your own commands by defining new methods or adding scripts to your class path. See the BeanShell user’s manual for more information.

One important BeanShell command is print(), which displays values. print( ) does pretty much the same thing as System.out.println( ) except that it insures that the ouput always goes to the command line (if you have multiple windows open). print( ) also displays some types of objects (such as arrays) more verbosely than Java would. Another very useful command is show( ), which toggles on and off automatic print( )ing of the result of every line you type. (Turn this on if you want to see every result.)

Here are a few other examples of BeanShell commands:

source(), run( )

Read a bsh script into this interpreter, or run it in a new interpreter

frame( )

Display an AWT or Swing component in a frame

load(), save( )

Load or save serializable objects (such as Java Beans)

cd(), cat(), dir(), pwd( ), etc.

Unix-like shell commands

exec( )

Run a native application

See the BeanShell user’s manual for a full list of commands.