public class RubyServlet extends HttpServlet {

  private static final long serialVersionUID = 5609571251958664412L;

  @Override
  protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

    String script = req.getParameter("ruby-script");

    ScriptingContainer scriptingContainer = new ScriptingContainer(LocalContextScope.SINGLETHREAD, LocalVariableBehavior.TRANSIENT);
    try{
    scriptingContainer.setCompileMode(org.jruby.RubyInstanceConfig.CompileMode.OFF);
    scriptingContainer.setCompatVersion(CompatVersion.RUBY1_9);
    scriptingContainer.setRunRubyInProcess(false);
    RubyInstanceConfig config = scriptingContainer.getProvider().getRubyInstanceConfig();
    config.setCextEnabled(false);
    config.setHardExit(false);
    config.setNativeEnabled(false);
    config.setRunRubyInProcess(false);
    config.setShouldCheckSyntax(true);
    config.setUpdateNativeENVEnabled(false);
    Object result = scriptingContainer.runScriptlet(script);

    resp.getWriter().format("Result is: %s", result);
    }finally{
      scriptingContainer.terminate();
    } 
  }
}

VII 26, 2013 6:57:35 DOP. org.apache.catalina.core.StandardService stopInternal
INFO: Stopping service Catalina
VII 26, 2013 6:57:36 DOP. org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [/test] appears to have started a thread named [FileWatchdog] but has failed to stop it. This is very likely to create a memory leak.
VII 26, 2013 6:57:36 DOP. org.apache.catalina.loader.WebappClassLoader checkThreadLocalMapForLeaks
SEVERE: The web application [/test] created a ThreadLocal with key of type [org.joni.StackMachine$1] (value [org.joni.StackMachine$1@13ec94f]) and a value of type [java.lang.ref.WeakReference] (value [java.lang.ref.WeakReference@112871a]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
VII 26, 2013 6:57:36 DOP. org.apache.catalina.loader.WebappClassLoader checkThreadLocalMapForLeaks
SEVERE: The web application [/test] created a ThreadLocal with key of type [org.joni.StackMachine$1] (value [org.joni.StackMachine$1@13ec94f]) and a value of type [java.lang.ref.WeakReference] (value [java.lang.ref.WeakReference@163d93b]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
VII 26, 2013 6:57:36 DOP. org.apache.catalina.loader.WebappClassLoader checkThreadLocalMapForLeaks
SEVERE: The web application [/test] created a ThreadLocal with key of type [org.joni.StackMachine$1] (value [org.joni.StackMachine$1@13ec94f]) and a value of type [java.lang.ref.WeakReference] (value [java.lang.ref.WeakReference@4ae99f]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
VII 26, 2013 6:57:36 DOP. org.apache.catalina.loader.WebappClassLoader checkThreadLocalMapForLeaks
VII 26, 2013 6:57:36 DOP. org.apache.coyote.AbstractProtocol stop
INFO: Stopping ProtocolHandler ["http-bio-8042"]