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POJPA @OneToOne throws Error when mapped to an abstract @Entity with subclasses
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copied!<p>I have a problem when an Entity is mapped to another Entity which has a direct implementation on its subclasses. See sample mapping below:</p> <pre><code>@Entity class Location { @OneToOne @JoinColumn(...) private Person person; } @Entity @Inheritance(strategy=InheritanceType.SINGLE_TABLE) @DiscriminatorColumn(name="person_type",discriminatorType=DiscriminatorType.STRING) abstract class Person { } @Entity @DiscriminatorValue("M") class Man extends Person { ... } @Entity @DiscriminatorValue("W") class Woman extends Person { ... } </code></pre> <p>Now, this is what I have on my database table:</p> <p>location-table: id=1, person_id=1 person-table: id=1,person_type="M"</p> <p>When I retrieve the Location using entity manager, hibernate throws an exception saying that i cannot instantiate an abstract class or an interface.</p> <pre><code>Location location = entityManager.find(Location.class, 1L); </code></pre> <p>Hibernate throws this error:</p> <pre><code>javax.persistence.PersistenceException: org.hibernate.InstantiationException: Cannot instantiate abstract class or interface: Person at org.hibernate.ejb.AbstractEntityManagerImpl.throwPersistenceException(AbstractEntityManagerImpl.java:630) at org.hibernate.ejb.AbstractEntityManagerImpl.find(AbstractEntityManagerImpl.java:195) at ...... at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:585) at org.junit.internal.runners.TestMethod.invoke(TestMethod.java:59) at org.junit.internal.runners.MethodRoadie.runTestMethod(MethodRoadie.java:98) at org.unitils.UnitilsJUnit4TestClassRunner$TestListenerInvokingMethodRoadie.runTestMethod(UnitilsJUnit4TestClassRunner.java:174) at org.junit.internal.runners.MethodRoadie$2.run(MethodRoadie.java:79) at org.junit.internal.runners.MethodRoadie.runBeforesThenTestThenAfters(MethodRoadie.java:87) at org.unitils.UnitilsJUnit4TestClassRunner$TestListenerInvokingMethodRoadie.runBeforesThenTestThenAfters(UnitilsJUnit4TestClassRunner.java:156) at org.junit.internal.runners.MethodRoadie.runTest(MethodRoadie.java:77) at org.junit.internal.runners.MethodRoadie.run(MethodRoadie.java:42) at org.unitils.UnitilsJUnit4TestClassRunner.invokeTestMethod(UnitilsJUnit4TestClassRunner.java:95) at org.junit.internal.runners.JUnit4ClassRunner.runMethods(JUnit4ClassRunner.java:51) at org.unitils.UnitilsJUnit4TestClassRunner.access$000(UnitilsJUnit4TestClassRunner.java:44) at org.unitils.UnitilsJUnit4TestClassRunner$1.run(UnitilsJUnit4TestClassRunner.java:62) at org.junit.internal.runners.ClassRoadie.runUnprotected(ClassRoadie.java:27) at org.junit.internal.runners.ClassRoadie.runProtected(ClassRoadie.java:37) at org.unitils.UnitilsJUnit4TestClassRunner.run(UnitilsJUnit4TestClassRunner.java:68) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197) </code></pre>

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