Attach a clojure / scala repl to a running JVM

Question

I have a java web application running under tomcat in a Sun java 6 JVM. Is there a way to attach a scala or clojure REPL to the running JVM ?

Once the webapp is up and

Answer 1

There's no way to attach a REPL to an already-running JVM, so you need to think about the problem backwards...

Start the REPL on the server, either when the program is launched or in response to a inbound client connection (using e.g. Telnet).

There's a good example here: http://blog.homecloud.ca/2010/03/scripster-interactive-scala-repl-using.html

You could also host an Interpreter instance in your server, then expose a web interface. This is the approach taken by http://www.simplyscala.com/

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If you're thinking of debugging, then you'd be better served by this answer: Drop into interpreter during arbitrary scala code location