Increase JVM heap size for Scala?

Question

I have a Scala data processing tool which is failing with a java.lang.OutOfMemoryError exception. The tool needs to make a couple passes over a large data file (the one I'm working on is over 700MB), so it would be convenient if the entire thing could be stored in memory.

I run the tool from the command line or from a Bash script using the "scala" runner. How do I increase the JVM heap size for this? I've tried passing -Xmx1024m, but it does not recognize this argument. I'm using a nightly build of Scala 2.8.0 (r18678).

Answer 1

The JAVA_OPTS environment variable is used to specify the options passed to the java command. See the Scala manpage for details.

Answer 2

You can pass options to the JVM via -J. E.g.,

scala -J-Xmx2g ...

Answer 3

Edit JAVA_OPTS.

Answer 4

Based on Joe's suggestion, I looked at the scala program, which is a Bash script that calls java with various Scala specific arguments. It allows extra command line arguments to be passed to Java through the JAVA_OPTS environment variable. So you can increase the heap size like this:

JAVA_OPTS="-Xmx2g" scala classname arguments...

Answer 5

As a hack you can edit the scala/bin/scala file to edit the parameters for the java command. Not pretty.