Java.io.ObjectInputStream.defaultReadObject() Method

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Description

The java.io.ObjectInputStream.defaultReadObject() method read the non-static and non-transient fields of the current class from this stream. This may only be called from the readObject method of the class being deserialized. It will throw the NotActiveException if it is called otherwise.

Declaration

Following is the declaration for java.io.ObjectInputStream.defaultReadObject() method

public void defaultReadObject()

Parameters

  • NA

Return Value

This method does not return a value.

Exception

  • ClassNotFoundException -- if the class of a serialized object could not be found.

  • IOException -- if an I/O error occurs.

  • NotActiveException -- if the stream is not currently reading objects.

Example

The following example shows the usage of java.io.ObjectInputStream.defaultReadObject() method.

package com.tutorialspoint;

import java.io.*;

public class ObjectInputStreamDemo {

   public static void main(String[] args) {

      try {

         // create a new file with an ObjectOutputStream
         FileOutputStream out = new FileOutputStream("test.txt");
         ObjectOutputStream oout = new ObjectOutputStream(out);

         // write something in the file
         oout.writeObject(new Example());
         oout.flush();

         // create an ObjectInputStream for the file we created before
         ObjectInputStream ois =
                 new ObjectInputStream(new FileInputStream("test.txt"));

         // read the object and print the string
         Example a = (Example) ois.readObject();

         // print the string that is in Example class
         System.out.println("" + a.s);


      } catch (Exception ex) {
         ex.printStackTrace();
      }


   }

   static class Example implements Serializable {

      String s = "Hello World!";

      private void readObject(ObjectInputStream in)
              throws IOException, ClassNotFoundException {
         in.defaultReadObject();

      }
   }
}

Let us compile and run the above program, this will produce the following result:

Hello World



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