> For the complete documentation index, see [llms.txt](https://yunaeecy.gitbook.io/wiki/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://yunaeecy.gitbook.io/wiki/java/serializable.md).

# serializable

Serializable is a marker interface in Java[1](https://docs.oracle.com/javase/8/docs/api/java/io/Serializable.html)[2](https://www.geeksforgeeks.org/serialization-in-java/)[3](https://www.digitalocean.com/community/tutorials/serialization-in-java)[4](https://docs.oracle.com/javase/tutorial/jndi/objects/serial.html)[5](https://www.baeldung.com/java-serialization)[6](https://www.javatpoint.com/serialization-in-java). It is used to **indicate** that **a class can be serialized**, which means **its state can be converted into a byte stream**[2](https://www.geeksforgeeks.org/serialization-in-java/)[3](https://www.digitalocean.com/community/tutorials/serialization-in-java)[4](https://docs.oracle.com/javase/tutorial/jndi/objects/serial.html)[5](https://www.baeldung.com/java-serialization)[6](https://www.javatpoint.com/serialization-in-java). Serialization is the process of **converting an object's state into a format that can be stored or transmitted** and later deserialized back into an object[2](https://www.geeksforgeeks.org/serialization-in-java/)[3](https://www.digitalocean.com/community/tutorials/serialization-in-java)[4](https://docs.oracle.com/javase/tutorial/jndi/objects/serial.html)[5](https://www.baeldung.com/java-serialization)[6](https://www.javatpoint.com/serialization-in-java).To make a class serializable, it needs to implement the Serializable interface[2](https://www.geeksforgeeks.org/serialization-in-java/)[3](https://www.digitalocean.com/community/tutorials/serialization-in-java)[4](https://docs.oracle.com/javase/tutorial/jndi/objects/serial.html)[6](https://www.javatpoint.com/serialization-in-java). This interface acts as a flag to the Java runtime that the class can be serialized[1](https://docs.oracle.com/javase/8/docs/api/java/io/Serializable.html). It is a marker interface because it does not contain any methods or fields to implement[1](https://docs.oracle.com/javase/8/docs/api/java/io/Serializable.html)[2](https://www.geeksforgeeks.org/serialization-in-java/)[3](https://www.digitalocean.com/community/tutorials/serialization-in-java)[6](https://www.javatpoint.com/serialization-in-java).When a class implements Serializable, all of its subtypes are also considered serializable[1](https://docs.oracle.com/javase/8/docs/api/java/io/Serializable.html)[5](https://www.baeldung.com/java-serialization).However, if a class has a reference to another object, both the class and the referenced object must implement Serializable, or else a NotSerializableException will be thrown[5](https://www.baeldung.com/java-serialization).