Deadlock example in Java

DeadlockExample.java

public class DeadlockExample {

    private static final int NUM_THREADS = 20;
    private static final int NUM_ACCOUNTS = 5;
    private static final int NUM_ITERATIONS = 1000000;

    public static void main(String[] args) {
        final Random rnd = new Random();
        final Account[] accounts = loadAllAccounts();

        class TransferThread extends Thread {
            private int id;
            TransferThread(int id) {
                this.id = id;
            }

            @Override
            public void run() {
                for (int i = 0; i < NUM_ITERATIONS; i++) {
                    log("[STARTED] Iteration " + i);
                    // simulates dead lock
                    int fromAcct = rnd.nextInt(NUM_ACCOUNTS);
                    int toAcct = rnd.nextInt(NUM_ACCOUNTS);
                    log("[TRYING] Thread-" + id + " TRYING to acquire lock for Account-" + fromAcct);
                    synchronized (accounts[fromAcct]) {
                        log("[LOCKED] Thread-" + id + " ACQUIRED lock for Account-" + fromAcct);
                        log("[TRYING] Thread-" + id + " TRYING to acquire lock for Account-" + toAcct);
                        synchronized (accounts[toAcct]) {
                            log("[LOCKED] Thread-" + id + " ACQUIRED lock for Account-" + toAcct);
                            // DO SOMETHING WITH ACCOUNTS
                            log("[TRANSFERED] Thread-" + id + " from Account-" + fromAcct + " to Account-" + toAcct);
                            log("[RELEASED] Thread-" + id + " RELEASED lock for Account-" + toAcct);
                        }
                        log("[RELEASED] Thread-" + id + " RELEASED lock for Account-" + fromAcct);
                    }
                    log("[ENDED] Iteration " + i);
                }
            }

            private void log(String text) {
                System.out.println(text);
            }
        }

        // starts all threads
        for (int i = 0; i < NUM_THREADS; i++) {
            new TransferThread(i).start();
        }
    }

    private static Account[] loadAllAccounts() {
        return IntStream
                .range(0, NUM_ACCOUNTS)
                .mapToObj(Account::new)
                .toArray(Account[]::new);
    }

    static class Account {
        private int id;
        Account(int id) {
            this.id = id;
        }
    }
}