ObjectInputStream enableResolveObject() method in Java with examples

Last Updated : 05 Jun, 2020

The enableResolveObject() method of the ObjectInputStream class in Java is used to enables the stream to do replacement of objects read from the stream. When enabled, the resolveObject(java.lang.Object) method is called for every object being deserialized.

Syntax:

protected boolean enableResolveObject(
                        boolean enable)

Parameters: This method accepts only single parameter.

enable: This parameter is set to true to enable use of resolveObject() for each object being deserialized.

Return Value: This method returns the previous setting before this method was invoked.

Errors and Exceptions: The function throws SecurityException if a security manager exists and its checkPermission method denies enabling the stream to do replacement of objects read from the stream.

Below program illustrate the above method:

Program 1:

Java

// Java program to illustrate 
// the above method 
  
import java.io.*; 
  
public class GFG 
    extends ObjectInputStream { 
  
    public GFG(InputStream in) 
        throws IOException 
    { 
        super(in); 
    } 
  
    public static void main(String[] args) 
    { 
        String s = "Geeksforgeeks"; 
        try { 
  
            // create a new file 
            // with an ObjectOutputStream 
            FileOutputStream out 
                = new FileOutputStream("Shubham.txt"); 
  
            ObjectOutputStream out1 
                = new ObjectOutputStream(out); 
  
            // write 
            out1.writeUTF(s); 
  
            // Flushes the stream 
            out1.flush(); 
  
            // create an ObjectInputStream 
            // for the file 
            GFG example 
                = new GFG( 
                    new FileInputStream("Shubham.txt")); 
  
            System.out.println( 
                example 
                    .resolveObject( 
                        example.readUTF())); 
  
            System.out.println( 
                example 
                    .enableResolveObject(true)); 
        } 
  
        catch (Exception ex) { 
            ex.printStackTrace(); 
        } 
    } 
} 

Output:

Program 2:

Java

// Java program to illustrate 
// the above method 
  
import java.io.*; 
import java.io.InputStream; 
  
public class GFG 
    extends ObjectInputStream { 
  
    public GFG(InputStream in) 
        throws IOException 
    { 
        super(in); 
    } 
  
    public static void main(String[] args) 
        throws IOException 
    { 
  
        int[] array = { 1, 34, 23, 425, 69, 22 }; 
  
        try { 
  
            // create a new file 
            // with an ObjectOutputStream 
            FileOutputStream out 
                = new FileOutputStream("Shubham.txt"); 
  
            DataOutputStream out1 
                = new DataOutputStream(out); 
  
            // write 
            // for each byte in the buffer 
            for (int val : array) { 
  
                // write character to the dos 
                out1.writeInt(val); 
            } 
  
            // Flushes the stream 
            out1.flush(); 
  
            // create an ObjectInputStream 
            // for the file 
            DataInputStream example 
                = new DataInputStream( 
                    new FileInputStream("Shubham.txt")); 
  
            for (int i = 0; i <= array.length; i++) { 
                int c = example.readInt(); 
                System.out.print(c + " "); 
            } 
            System.out.print("\n"); 
        } 
  
        catch (Exception ex) { 
        } 
    } 
}