Java - ObjectStreamClass

Last Updated : 24 Jan 2026

The ObjectStreamClass in Java is used as a serialization descriptor that contains metadata about a serializable class.

In this chapter, we will learn what the ObjectStreamClass is, why it is used, its fields, important methods, and how it works with an example.

What is ObjectStreamClass in Java?

The ObjectStreamClass is a special class used internally by Java serialization, and it is used to store metadata of a class such as its name, fields, and serialVersionUID.

It acts as a serialization descriptor, which means it describes how a class is represented during the serialization and deserialization process.

ObjectStreamClass Usage (No Public Constructor)

The ObjectStreamClass does not provide a public constructor. Instead, objects of this class are obtained using static lookup methods provided by the class.

Here is the common way to obtain ObjectStreamClass:

Fields of ObjectStreamClass

The ObjectStreamClass provides fields that describe serializable properties.

Modifier and Type	Field	Description
static ObjectStreamField[]	NO_FIELDS	Indicates that the class has no serializable fields

Methods of ObjectStreamClass

The ObjectStreamClass class provides methods to access serialization-related information.

Modifier and Type	Method	Description
Class<?>	forClass()	It returns the class in the local VM that this version is mapped to.
ObjectStreamField	getField(String name)	It gets the field of this class by name.
ObjectStreamField[]	getFields()	It returns an array of the fields of this serialization class.
String	getName()	It returns the name of the class described by this descriptor.
long	getSerialVersionUID()	It returns the serialVersionUID for this class.
Static ObjectStreamClass	lookup(Class<?> cl)	It finds the descriptor for a class that can be serialized.
Static ObjectStreamClass	lookupAny(Class<?> cl)	It returns the descriptor for any class, regardless of whether it implements Serializable.
String	toString()	It returns a string describing this ObjectStreamClass.

Example of ObjectStreamClass

This example demonstrates how to retrieve serialization-related information of a class using ObjectStreamClass.

import java.io.ObjectStreamClass;
import java.util.Calendar;

public class ObjectStreamClassExample {
	public static void main(String[] args) {

		// create a new object stream class for Integers
		ObjectStreamClass osc = ObjectStreamClass.lookup(SmartPhone.class);

		// get the value field from ObjectStreamClass for integers
		System.out.println("" + osc.getField("price"));

		// create a new object stream class for Calendar
		ObjectStreamClass osc2 = ObjectStreamClass.lookup(String.class);

		// get the Class instance for osc2
		System.out.println("" + osc2.getField("hash"));

	}
}

Output:

I price
null

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