Java Single Instance Lock. Creates a simple and reliable lock file that is cross platform JavaFX, Java

gistfile1.java

private static boolean lockInstance(final String lockFile) {
	try {
		final File file = new File(lockFile);
		final RandomAccessFile randomAccessFile = new RandomAccessFile(file, "rw");
		final FileLock fileLock = randomAccessFile.getChannel().tryLock();
		if (fileLock != null) {
			Runtime.getRuntime().addShutdownHook(new Thread() {
				public void run() {
					try {
						fileLock.release();
						randomAccessFile.close();
						file.delete();
					} catch (Exception e) {
						log.error("Unable to remove lock file: " + lockFile, e);
					}
				}
				});
			return true;
		}
	} catch (Exception e) {
		log.error("Unable to create and/or lock file: " + lockFile, e);
	}
	return false;
}

Originally found at http://www.rbgrn.net/content/43-java-single-application-instance#comment-1018