Static Method Synchronization

What happens when you try to synchronize on a static method? When a static synchronized method is called, which object are we referring to? A static method does not have a notion of a this reference. It is not possible to obtain a lock on an object that does not exist.

Hashcodes in Java

What happens if two different object hash to the same hashcode and then are placed in a HashMap?

Method Synchronization

In Java, access to shared resources can be controlled by using synchronized methods. An instance method is declared to be a synchronized method by adding the modifier synchronized to its declaration. For example:

How to SSH without using a Password

The basis of using ssh without typing your password is public key based authentication. You need to generate a pair of public/private keys for this.