See also the
secton of the user's manual.
What is BeanShell?
BeanShell is a small, free, embeddable Java source interpreter with
object scripting language features, written in Java. BeanShell dynamically
executes standard Java syntax and extends it with common scripting conveniences
such as loose types, commands, and method closures like those in
You can use BeanShell interactively for Java experimentation and
debugging as well as to extend your applications in new ways.
Scripting Java lends itself to a wide variety of applications including
rapid prototyping, user scripting extension, rules engines, configuration,
testing, dynamic deployment, embedded systems, and even Java education.
BeanShell is small and embeddable, so you can call BeanShell from your
Java applications to execute Java code dynamically at run-time or to
provide extensibility in your applications. Alternatively, you
can use standalone BeanShell scripts to manipulate Java applications;
working with Java objects and APIs dynamically.
Since BeanShell is written in Java and runs
in the same VM as your application, you can freely pass references to
"live" objects into scripts and return them as results.
In short, BeanShell is dynamically interpreted Java, plus a scripting
language and flexible environment all rolled into one clean package.
Summary of features
- Dynamic execution of the full Java syntax, Java code fragments, as well
as loosely typed Java and additional scripting conveniences.
- Transparent access to all Java objects and APIs.
- Runs in four modes: Command Line, Console, Applet, Remote Session
- Can work in security constrained environments without a classloader or
bytecode generation for most features.
- The interpreter is small ~150K jar file.
- Pure Java.
- It's Free!!
Java evaluation features:
- Evaluate full Java source classes dynamically as well as isolated
Java methods, statements, and expressions.
- Optionally typed variables.
- Scripted methods with optionally typed arguments and return values
- Scripted objects (method closures)
- Scripted interfaces and event handlers.
- Convenience syntax for working with JavaBean properties, hashtables, and
primitive wrapper types.
- Auto-allocation of variables to emulate Java properties files.
- Extensible set of utility and shell-like commands
- Dynamic classpath management including find grained class reloading
- Dynamic command loading and user command path
- Sophisticated namespace and callstack management
- Detailed error reporting
- Interactive Java - try out object features, APIs and GUI widgets
- "hands on".
- Scripting extension for applications - Allow your applications to be
extended via scripts in an intuitive and simple way.
- Macro Languages - Generate scripts as macros and execute them live in your
- Education - Teach Java in a hands-on, live environment
- Expression evaluator for scientific, financial apps and rules engines -
evaluate complex expressions with conditions and loops.
- Remote debugging - Embed a live, remotely accessible shell / command line
in your application with just a few lines of code.
- Use BeanShell declaratively to replace properties files and replace startup
config files with real scripts that perform complex initialization and setup
with the full Java syntax at their disposal.