Java Transient Keyword

Java transient keyword is used in serialization. If you define any data member as transient, it will not be serialized.
Let's take an example, I have declared a class as Employee, it has three data members id, name, and age. If you serialize the object, all the values will be serialized but I don't want to serialize one value, e.g. age then we can declare the age data member as transient.

Example of Java Transient Keyword

In this example, we have created the two classes Employee and SerializationWithTransient. The age data member of the Employee class is declared as transient, its value will not be serialized.

If you deserialize the object, you will get the default value for the transient variable.

Let's create a Employee class with a transient variable age.

class Employee implements Serializable {
 
 private static final long serialVersionUID = 1L;
 private int id;
 private String name;
 private transient int age;
 
 public int getId() {
  return id;
 }

 public void setId(int id) {
  this.id = id;
 }

 public String getName() {
  return name;
 }

 public void setName(String name) {
  this.name = name;
 }
 
 public int getAge() {
  return age;
 }
 
 public void setAge(int age) {
  this.age = age;
 }
}

Now write the code to serialize and deserialize the object. 

In the example, serilizeProcessing() and deSerilizeProcessing() private methods perform serialization and deserialization.

public class SerializationWithTransient {

 public static void main(String[] args) throws IOException, ClassNotFoundException {
  final Employee employee = new Employee();
  employee.setId(100);
  employee.setName("ramesh");
  employee.setAge(100);
  serilizeProcessing(employee);
  deSerilizeProcessing();
 }
 
 private static void serilizeProcessing(Employee employee)
   throws IOException {
  final FileOutputStream fout = new FileOutputStream("f.txt");
  final ObjectOutputStream out = new ObjectOutputStream(fout);
  out.writeObject(employee);
  out.flush();
  out.close();
  System.out.println("success");
 }

 private static void deSerilizeProcessing() throws IOException, ClassNotFoundException {
  final ObjectInputStream in = new ObjectInputStream(new FileInputStream(
    "f.txt"));
  final Employee employee = (Employee) in.readObject();
  System.out.println(" printing employee object details");
  System.out.println(" printing employee age which is transient field");
  System.out.println(employee.getId() + "  " + employee.getName() + "  " + employee.getAge());
  in.close();
 }
 
}

Related Posts

• Guide to Serialization in Java

• Guide to the understanding of serialVersionUID