https://github.com/javaee/jpa-spec: Java(TM) Persistence API 
Copyright (c) 2008 - 2013 Oracle Corporation. All rights reserved.
This program and the accompanying materials are made available under the
terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
which accompanies this distribution.
The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
and the Eclipse Distribution License is available at
http://www.eclipse.org/org/documents/edl-v10.php.
Contributors:
    Linda DeMichiel - Java Persistence 2.1
    Linda DeMichiel - Java Persistence 2.0

/*******************************************************************************
 * Copyright (c) 2008 - 2013 Oracle Corporation. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0
 * which accompanies this distribution.
 * The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *     Linda DeMichiel - Java Persistence 2.1
 *     Linda DeMichiel - Java Persistence 2.0
 *
 ******************************************************************************/ 
package javax.persistence;

import java.lang.annotation.Target;
import java.lang.annotation.Retention;
import java.lang.annotation.Documented;
import static java.lang.annotation.ElementType.TYPE;
import static java.lang.annotation.RetentionPolicy.RUNTIME;


Designates a class whose mapping information is applied 
to the entities that inherit from it. A mapped superclass 
has no separate table defined for it.  

 A class designated with the MappedSuperclass 
annotation can be mapped in the same way as an entity except that the 
mappings will apply only to its subclasses since no table 
exists for the mapped superclass itself. When applied to the 
subclasses the inherited mappings will apply in the context 
of the subclass tables. Mapping information may be overridden 
in such subclasses by using the AttributeOverride and 
AssociationOverride annotations or corresponding XML elements.

   Example: Concrete class as a mapped superclass
   @MappedSuperclass
   public class Employee {
   
       @Id protected Integer empId;
       @Version protected Integer version;
       @ManyToOne @JoinColumn(name="ADDR")
       protected Address address;
   
       public Integer getEmpId() { ... }
       public void setEmpId(Integer id) { ... }
       public Address getAddress() { ... }
       public void setAddress(Address addr) { ... }
   }
   
   // Default table is FTEMPLOYEE table
   @Entity
   public class FTEmployee extends Employee {
   
       // Inherited empId field mapped to FTEMPLOYEE.EMPID
       // Inherited version field mapped to FTEMPLOYEE.VERSION
       // Inherited address field mapped to FTEMPLOYEE.ADDR fk
   
       // Defaults to FTEMPLOYEE.SALARY
       protected Integer salary;
   
       public FTEmployee() {}
   
       public Integer getSalary() { ... }
   
       public void setSalary(Integer salary) { ... }
   }
   
   @Entity @Table(name="PT_EMP")
   @AssociationOverride(
       name="address", 
       joincolumns=@JoinColumn(name="ADDR_ID"))
   public class PartTimeEmployee extends Employee {
   
       // Inherited empId field mapped to PT_EMP.EMPID
       // Inherited version field mapped to PT_EMP.VERSION
       // address field mapping overridden to PT_EMP.ADDR_ID fk
       @Column(name="WAGE")
       protected Float hourlyWage;
   
       public PartTimeEmployee() {}
   
       public Float getHourlyWage() { ... }
       public void setHourlyWage(Float wage) { ... }
   }



See Also:
Since:Java Persistence 1.0
/**
 * Designates a class whose mapping information is applied 
 * to the entities that inherit from it. A mapped superclass 
 * has no separate table defined for it.  
 *
 * <p> A class designated with the <code>MappedSuperclass</code> 
 * annotation can be mapped in the same way as an entity except that the 
 * mappings will apply only to its subclasses since no table 
 * exists for the mapped superclass itself. When applied to the 
 * subclasses the inherited mappings will apply in the context 
 * of the subclass tables. Mapping information may be overridden 
 * in such subclasses by using the <code>AttributeOverride</code> and 
 * <code>AssociationOverride</code> annotations or corresponding XML elements.
 *
 * <pre>
 *    Example: Concrete class as a mapped superclass
 *
 *    &#064;MappedSuperclass
 *    public class Employee {
 *    
 *        &#064;Id protected Integer empId;
 *        &#064;Version protected Integer version;
 *        &#064;ManyToOne &#064;JoinColumn(name="ADDR")
 *        protected Address address;
 *    
 *        public Integer getEmpId() { ... }
 *        public void setEmpId(Integer id) { ... }
 *        public Address getAddress() { ... }
 *        public void setAddress(Address addr) { ... }
 *    }
 *    
 *    // Default table is FTEMPLOYEE table
 *    &#064;Entity
 *    public class FTEmployee extends Employee {
 *    
 *        // Inherited empId field mapped to FTEMPLOYEE.EMPID
 *        // Inherited version field mapped to FTEMPLOYEE.VERSION
 *        // Inherited address field mapped to FTEMPLOYEE.ADDR fk
 *    
 *        // Defaults to FTEMPLOYEE.SALARY
 *        protected Integer salary;
 *    
 *        public FTEmployee() {}
 *    
 *        public Integer getSalary() { ... }
 *    
 *        public void setSalary(Integer salary) { ... }
 *    }
 *    
 *    &#064;Entity &#064;Table(name="PT_EMP")
 *    &#064;AssociationOverride(
 *        name="address", 
 *        joincolumns=&#064;JoinColumn(name="ADDR_ID"))
 *    public class PartTimeEmployee extends Employee {
 *    
 *        // Inherited empId field mapped to PT_EMP.EMPID
 *        // Inherited version field mapped to PT_EMP.VERSION
 *        // address field mapping overridden to PT_EMP.ADDR_ID fk
 *        &#064;Column(name="WAGE")
 *        protected Float hourlyWage;
 *    
 *        public PartTimeEmployee() {}
 *    
 *        public Float getHourlyWage() { ... }
 *        public void setHourlyWage(Float wage) { ... }
 *    }
 * </pre>
 *
 * @see AttributeOverride 
 * @see AssociationOverride
 * @since Java Persistence 1.0
 */
@Documented
@Target({TYPE})
@Retention(RUNTIME)
public @interface MappedSuperclass {
}