Wonders of Code - Simplicity vs. Robustness In Lock File Handling (http://wp.me/p3ui6n-1k) - the (overly) simple design

SimpleSingletonBatchJob.java

public class SimpleSingletonBatchJob {
    private static boolean getLock() {
        File file = new File(LOCK_DIRECTORY+File.separatorChar+Configuration.getGroupPrefix());
        try {
            return file.createNewFile();
        } catch (IOException e) {
            return false;
        }
    }

    private static void releaseLock() {
        File file = new File(LOCK_DIRECTORY+File.separatorChar+Configuration.getGroupPrefix());
        file.delete();
    }


    public static void exit(int nr) {
        releaseLock();
        System.exit(nr);
    }

    public static void main(String[] args) throws IOException {
        ...
        if (! getLock()) { // #1 try to create lock
            System.out.println("Already running");
            return;
        }
        ... // do the job (may throw exceptions)
        
        releaseLock(); // #2 release lock when done
    }
}