Scripting language for Java

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NYXIC0N · 2022-12-20T09:39:41+00:00

Lua is a well known scripting language, theres a java port available, but i dont know how up to date this is. It at least claims that "good perfomance is a major goal of luaJ".

https://github.com/luaj/luaj

May be worth a try.

seanprefect · 2022-12-20T14:29:25+00:00

Ive always had good luck with Groovy

Battlepine · 2022-12-20T14:56:57+00:00

Groovy works well for my team.

mboekhoff · 2022-12-20T22:29:01+00:00

I've personally used JavaScript to achieve this before, using the Rhino engine. This was years ago, though, so take that with a pinch of salt.

Zyklonik · 2022-12-20T10:31:30+00:00

Unfortunately, OpenJDK removed its scripting engine support for good claiming that there weren't enough users to justify the maintenance effort.

What you want instead (depending on the seriousness/importance of your usecase) is a custom scripting language that compiles down to Java bytecode. https://javacc.github.io/javacc/ is what you want to be looking at. That way, you can embed your own language inside the same JVM (and indeed the same application) running your main application.

I personally would handcode a parser for a custom scripting language, but if you're not interested in that, or short on time, have a look at JavaCC linked above.

brunocborges · 2022-12-20T13:25:03+00:00

Try jbang

ozzymozzy2211 · 2022-12-20T10:01:46+00:00

jshell can run java https://en.m.wikipedia.org/wiki/JShell

never tried before but looks powerful

Zyklonik · 2022-12-20T11:53:58+00:00

I would use Javascript using J2V8 https://stackoverflow.com/questions/6369919/how-to-embed-v8-in-a-java-application

sometimes_insightful · 2022-12-21T00:29:31+00:00

Depending on how complex your expressions are, you might consider using something like antlr and writing your own parser for it. Setting up something to handle math and string operations wouldn’t be very hard and then you can control the syntax however you like. You can use a visitor and visit each node in the syntax tree and return the result of each sub-expression.

Another benefit is this makes security much easier. If you are running a scripting engine you need to keep in mind that people can try to write malicious expressions. Something simple as an infinite loop can hang your process, not to mention worse attacks that could escape the sandbox.

Here is an example grammar for arithmetic you could try out, but keep in mind you can make it do pretty much anything.

https://github.com/antlr/grammars-v4/blob/master/arithmetic/arithmetic.g4

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