How to Fix Java.IO.StreamCorruptedException: Invalid Stream Header

This tutorial demonstrates how to fix Java’s java.io.StreamCorruptedException: invalid stream header exception.

java.io.StreamCorruptedException: invalid stream header in Java

The java.io.StreamCorruptedException: invalid stream header is relatively a common exception. To understand the reason for this exception, we need to see the invalid stream header in the exception because it can explain the reason behind the issue.

The StreamCorruptedException has two constructors, the first with one argument and the other without arguments. The one who accepts the arguments describes the reasons for the exception.

The java.io.StreamCorruptedException: invalid stream header: XXXXXX is the exception with the argument where XXXXXX represents the invalid header details.

This exception commonly occurs when we are working with ObjectInputStream. Because, as per the Javadoc, only those objects can be read from streams that support the java.io.Serializable or java.io.Externalizable.

So whenever we use the ObjectInputStream, it should be used with the serialized data. Most of the StreamCorruptedException: invalid stream header occurs when a file such as text, HTML, XML, JSON, etc., is directly passed to the ObjectInputStream constructor rather than a serializable file.

Here are some commonly occurred java.io.StreamCorruptedException: invalid stream header with corresponding ASCII values.

Let’s try an example that will throw the java.io.StreamCorruptedException: invalid stream header exception. See example:

package delftstack;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.ClassNotFoundException;
import java.net.ServerSocket;
import java.net.Socket;

public class Example {
  private static ServerSocket Server_Socket;
  private static int Port_Number = 5000;

  public static void main(String args[]) throws IOException, ClassNotFoundException {
    Server_Socket = new ServerSocket(Port_Number);
    while (true) {
      System.out.println("Waiting for client request");
      // create socket and then wait for client connection
      Socket DemoSocket = Server_Socket.accept();
      // read from socket to the ObjectInputStream object
      ObjectInputStream Object_Input_Stream = new ObjectInputStream(DemoSocket.getInputStream());
      // convert the ObjectInputStream to the String
      String DemoMessage = (String) Object_Input_Stream.readObject();
      System.out.println("The Received Message is: " + DemoMessage);
      // ObjectOutputStream object
      ObjectOutputStream Object_Output_Stream =
          new ObjectOutputStream(DemoSocket.getOutputStream());
      // write object to the Socket
      Object_Output_Stream.writeObject("Hello Client " + DemoMessage);
      // close
      Object_Input_Stream.close();
      Object_Output_Stream.close();
      DemoSocket.close();
      // terminate the server on exit from the client
      if (DemoMessage.equalsIgnoreCase("exit"))
        break;
    }
    System.out.println("Shut down Socket server!!");
    // close the ServerSocket
    Server_Socket.close();
  }
}

The code above is trying to read a string sent from the client. The output for this code is the java.io.StreamCorruptedException: invalid stream header exception.

See output:

Exception in thread "main" java.io.StreamCorruptedException: invalid stream header: 54657374
    at java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:803)
    at java.io.ObjectInputStream.<init>(ObjectInputStream.java:298)
    at Example.main(SocketServerExample.java:29)

The reason for this exception is we are not sending the data using the ObjectOutputStream because we cannot expect the ObjectOutputStream to convert text to objects automatically; the hexadecimal value 54657374 is converted to Test as text, and we must be sending it directly as bytes.

We can use the methods readObject() and writeObject() to solve this problem.