code: public static boolean checkDot() throws IOException {
  		// call graphviz-dot via commons-exec
  		CommandLine cmdLine = new CommandLine(DOT_EXE);
  		cmdLine.addArgument("-V");
  		DefaultExecutor executor = new DefaultExecutor();
  		executor.setExitValue(0);
  		ExecuteWatchdog watchdog = new ExecuteWatchdog(60000);
  		executor.setWatchdog(watchdog);
  		executor.setStreamHandler(new PumpStreamHandler(System.out, System.err));
  		int exitValue = executor.execute(cmdLine);
  		if(exitValue != 0) {
  			System.err.println("Could not run '" + DOT_EXE + "', had exit value: " + exitValue + "!");
  			return false;
  		}
  
  		return true;
  	}
docs: Verify if dot can be started and print out the version to stdout.
  
  @return True if "dot -V" ran successfully, false otherwise
  
  @throws IOException If running dot fails.