When the NotSerializableException occurs ?

java.io.NotSerializableException is thrown when the object is not eligible for the serialization.

To fix this problem, implement the Serializable interface in the class.

Example

class Employee {

      private String empId;

      public String getEmpId() {

            return empId;

      }

      public void setEmpId(String empId) {

            this.empId = empId;

      }

}

/**

 Trying to serialize the non-Serializable object

 */

public class Test {

      public static void main(String[] args) throws IOException {

          // Create FileOutputStream to create file

          FileOutputStream out = new FileOutputStream("employee.dat");

          // Create ObjectOutputStream

          ObjectOutputStream outputStream = new ObjectOutputStream(out);

          // Create objects

          Employee obj = new Employee();

          obj.setEmpId("143011");

          // Write objects to stream

          outputStream.writeObject(obj);

          // Close the stream

          outputStream.close();

      }

}

Output

      Exception in thread "main" java.io.NotSerializableException: Employee

      at java.io.ObjectOutputStream.writeObject0(Unknown Source)

      at java.io.ObjectOutputStream.writeObject(Unknown Source)

      at Test.main(Test.java)

Solution

Just implement Serializable interface to the class which is being Serialized

class Employee implements Serializable {

   ...

}