Avoiding Deadlocks

• A deadlock occurs if no thread can proceed because each thread is waiting for another to do some work first
• BankAccount example

  public void withdraw(double amount)
  {
     balanceChangeLock.lock();
     try
     {
        while (balance < amount)
           Wait for the balance to grow
        . . .
     }
     finally
     {
        balanceChangeLock.unlock();
     }
  }