Persistent objects are objects that persist beyond their normal life span. All objects that are created in application are only accessible during the execution of the application. This is the normal life span for a non persistent object. The idea of persistent objects is to give the ability to objects to store themselves on some persistent stream (usually files), so that they may later be reconstructed. The action of storing an object on a persistent stream is called streaming, which is why persistent objects are also known as streamable objects.