Java Transient Modifier

A transient modifier applied to a field tells Java that this attribute should be excluded when the object is being serialized. When the object is being deserialized, the field will be initialized with its default value (this will typically be a null value for a reference type, or zero/ false if the object is a primitive type).

Where should we apply a transient modifier? When will it be useful?

Think of a User object. This User contains, among all its properties, login, email, and password. When the data is being serialized and transmitted through the network, we can think of a few security reasons why we would not like to send the field password together with the entire object. In this case, marking the field as transient will solve this security problem.

In summary: Use transient when an object contains sensitive data that you do not want to transmit, or when it contains data that you can derive from other elements. Static fields are implicitly transient.