What is Java Shutdown Hook?

The shutdown hook can be used to perform cleanup resource or save the state when JVM shuts down normally or abruptly. So if you want to execute some code before JVM shuts down, use shutdown hook.

public class MyShutdownHook {
	public static void main(String[] args) {
		System.out.println("Executing main Thread.");

		Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
			public void run() {
				System.out.println("Executing Shutdown hook Thread.");
			}
		}));

		System.out.println("Exiting main thread.");
	}
}

JVM shutdown sequence has 2 phases.

• All registered shutdown hooks are started in some unspecified order and allowed to run concurrently until they finish.
• All un-invoked finalizers are run if finalization-on-exit has been enabled.

Earn bitcoins upto $250 (free), invest in other Cryptocurrencies when you signup with blockfi. Use the referral link: Signup now and earn!

Using BlockFi, don't just buy crypto - start earning on it. Open an interest account with up to 8.6% APY, trade currencies, or borrow money without selling your assets.

Join CoinBase! We'll both receive $10 in free Bitcoin when they buy or sell their first $100 on Coinbase! Available in India also. Use the referral Join coinbase!

Invest now!!! Get Free equity stock (US, UK only)!

Use Robinhood app to invest in stocks. It is safe and secure. Use the Referral link to claim your free stock when you sign up!.

The Robinhood app makes it easy to trade stocks, crypto and more.

Webull! Receive free stock by signing up using the link: Webull signup.