Understanding the 'transient' Keyword in Java

The 'transient' keyword in a Java class denotes variables that cannot be serialized. Serialization in Java refers to the conversion of an object's state into a byte stream to save it to a storage medium or transmit it over a network. Conversely, deserialization converts the byte stream back into a copy of the object. It's a critical process for executing object-level storage and transmission.

Now, why would we want to mark a variable as 'transient'? It's because we might have some variables in our class whose state we don't want to save or transmit. These might be variables that hold temporary or sensitive data. In such a situation, we would use the transient keyword.

Let's look at a practical example:

public class MyData implements Serializable {
  private int a;
  private transient int b; // this will not be serialized
}

In the example above, b is marked as transient which means it will not be included while serializing instances of MyData.

When deserialized, transient variables will be assigned the default value for their data type. In the above code, if MyData object is serialized and then deserialized, b will be 0 as 0 is the default value for int.

As a best practice, it's essential to use the transient keyword wisely. For instance, it's not ideal to mark variables as transient if they are required for the logical consistency of objects after deserialization. It's also important to note that transient keyword is not applicable to static variables because static variables are part of the class, not objects, and serialization works on objects.

Understanding the transient keyword and proving its effective utilization in your Java applications will help with designing high-quality, efficient, and secure software solutions.