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Editing eclipse.ini



Fixing configuration issues of Eclipse


The eclipse.ini file must be edited to configure the JVM that Rascal uses to run its code. Reasons for configuring it are:

  • More stackspace is required to execute the embedded parser generator
  • More heap space is required to load all of the modules
  • The right JVM version needs to be configured (Java 11)

Steps to configure eclipse.ini

  1. Find the file first:
    • on MacOSX it may be in /Applications/
    • on Windows it may be in C:\Program Files\eclipse\eclipse.ini
    • on Linux its where you extracted the eclipse tarball.
  2. then find the line that starts with -vm and add on the next separate line the path to the java run-time binary
    • e.g. /usr/bin/java
    • e.g. C:\Program Files\Java SDK 1.8\bin\javaw (note there is no .exe).
  3. If you can’t find the line that starts with -vm you should add it before the line starting with -vmargs
  • Typically -Xss8m is enough stacksize
  • Typically -Xmx1G is enough heap size.
  • Rascal works with Java 11.


  • Re-installing Eclipse requires editing the ini file again.
  • Upgrading Java installation, and removing the old one, might invalidate the Eclipse configuration.
  • Rascal works only with Java 11.