ERROR - Hibernate - org.hibernate.MappingException: composite-id class must implement Serializable

Error

org.hibernate.MappingException: composite-id class must implement Serializable: 
 at org.hibernate.mapping.RootClass.checkCompositeIdentifier(RootClass.java:263)
 at org.hibernate.mapping.RootClass.validate(RootClass.java:244)
 at org.hibernate.cfg.Configuration.validate(Configuration.java:1362)
 at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1865)
Type
Runtime

Cause

Class with the composite Id is not implementing Serializable interface

Resolution

If you are using composite key in entity using IdClass, make sure that you have the class implementing Serializable interface

@Entity
@Table(name="SAMPLE_TABLE")
@IdClass(SampleEntity.class)
Class SampleEntity implements serializable {
@Id
private String name;

@Id
private String Deptt;
}