code: public static ScriptRunner createRunner() {
  		RunnerType t = runner.get();
  		
  		switch (t) {
  		case AUTO:
  			if (supportsV8()) {
  				return createV8Runner();
  			}
  			//fall back to JRE
  			return createJreRunner();
  		
  		case JRE:
  			return createJreRunner();
  		
  		case V8:
  			return createV8Runner();
  		
  		default:
  			throw new RuntimeException("Invalid runner type");
  		}
  	}
docs: Creates a new {@link ScriptRunner} instance according to the
  type set with {@link #setRunnerType(RunnerType)}
  @return the script runner