Question

I have a database table with 5 rows.

The first time I do a select all I get a StackOverflowError

em.createQuery("SELECT e FROM " + clazz.getSimpleName() + " e");

How ever if I do a single select on each of the rows

em.find(clazz, 1);
em.find(clazz, 2);
em.find(clazz, 3);
em.find(clazz, 4);
em.find(clazz, 5);

Then the select all works perfectly. I’m guessing this is something to do with the records not being in a cache yet?

Full stack trace is too long here is the top

java.lang.StackOverflowError
at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107)
at java.lang.ClassLoader.loadClass(Unknown Source)
at java.lang.ClassLoader.loadClassInternal(Unknown Source)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:427)
at com.mysql.jdbc.PreparedStatement.getInstance(PreparedStatement.java:872)
at com.mysql.jdbc.ConnectionImpl.clientPrepareStatement(ConnectionImpl.java:1498)
at com.mysql.jdbc.ConnectionImpl.prepareStatement(ConnectionImpl.java:4270)
at com.mysql.jdbc.ConnectionImpl.prepareStatement(ConnectionImpl.java:4169)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.prepareStatement(DatabaseAccessor.java:1401)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.prepareStatement(DatabaseAccessor.java:1350)
at org.eclipse.persistence.internal.databaseaccess.DatabaseCall.prepareStatement(DatabaseCall.java:652)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.basicExecuteCall(DatabaseAccessor.java:576)
at org.eclipse.persistence.internal.databaseaccess.DatabaseAccessor.executeCall(DatabaseAccessor.java:526)
at org.eclipse.persistence.sessions.server.ServerSession.executeCall(ServerSession.java:529)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:206)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.executeCall(DatasourceCallQueryMechanism.java:192)
at org.eclipse.persistence.internal.queries.DatasourceCallQueryMechanism.selectOneRow(DatasourceCallQueryMechanism.java:664)
at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.selectOneRowFromTable(ExpressionQueryMechanism.java:2582)
at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.selectOneRow(ExpressionQueryMechanism.java:2553)
at org.eclipse.persistence.queries.ReadObjectQuery.executeObjectLevelReadQuery(ReadObjectQuery.java:439)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeDatabaseQuery(ObjectLevelReadQuery.java:1076)
at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:740)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:1036)
at org.eclipse.persistence.queries.ReadObjectQuery.execute(ReadObjectQuery.java:407)
at org.eclipse.persistence.internal.sessions.AbstractSession.internalExecuteQuery(AbstractSession.java:2392)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1291)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1273)
at org.eclipse.persistence.internal.indirection.NoIndirectionPolicy.valueFromQuery(NoIndirectionPolicy.java:309)
at org.eclipse.persistence.mappings.ForeignReferenceMapping.valueFromRowInternal(ForeignReferenceMapping.java:1850)
at org.eclipse.persistence.mappings.OneToOneMapping.valueFromRowInternal(OneToOneMapping.java:1623)
at org.eclipse.persistence.mappings.ForeignReferenceMapping.valueFromRow(ForeignReferenceMapping.java:1739)
at org.eclipse.persistence.mappings.DatabaseMapping.readFromRowIntoObject(DatabaseMapping.java:1283)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildAttributesIntoObject(ObjectBuilder.java:342)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:717)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:504)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:454)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.buildObject(ObjectLevelReadQuery.java:723)
at org.eclipse.persistence.queries.ReadObjectQuery.executeObjectLevelReadQuery(ReadObjectQuery.java:448)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeDatabaseQuery(ObjectLevelReadQuery.java:1076)
at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:740)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:1036)
at org.eclipse.persistence.queries.ReadObjectQuery.execute(ReadObjectQuery.java:407)
at org.eclipse.persistence.internal.sessions.AbstractSession.internalExecuteQuery(AbstractSession.java:2392)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1291)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1273)
at org.eclipse.persistence.internal.indirection.NoIndirectionPolicy.valueFromQuery(NoIndirectionPolicy.java:309)
at org.eclipse.persistence.mappings.ForeignReferenceMapping.valueFromRowInternal(ForeignReferenceMapping.java:1850)
at org.eclipse.persistence.mappings.OneToOneMapping.valueFromRowInternal(OneToOneMapping.java:1623)
at org.eclipse.persistence.mappings.ForeignReferenceMapping.valueFromRow(ForeignReferenceMapping.java:1739)
at org.eclipse.persistence.mappings.DatabaseMapping.readFromRowIntoObject(DatabaseMapping.java:1283)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildAttributesIntoObject(ObjectBuilder.java:342)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:717)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:504)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:454)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.buildObject(ObjectLevelReadQuery.java:723)
at org.eclipse.persistence.queries.ReadObjectQuery.executeObjectLevelReadQuery(ReadObjectQuery.java:448)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeDatabaseQuery(ObjectLevelReadQuery.java:1076)
at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:740)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:1036)
at org.eclipse.persistence.queries.ReadObjectQuery.execute(ReadObjectQuery.java:407)
at org.eclipse.persistence.internal.sessions.AbstractSession.internalExecuteQuery(AbstractSession.java:2392)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1291)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1273)
at org.eclipse.persistence.internal.indirection.NoIndirectionPolicy.valueFromQuery(NoIndirectionPolicy.java:309)
at org.eclipse.persistence.mappings.ForeignReferenceMapping.valueFromRowInternal(ForeignReferenceMapping.java:1850)
at org.eclipse.persistence.mappings.OneToOneMapping.valueFromRowInternal(OneToOneMapping.java:1623)
at org.eclipse.persistence.mappings.ForeignReferenceMapping.valueFromRow(ForeignReferenceMapping.java:1739)
at org.eclipse.persistence.mappings.DatabaseMapping.readFromRowIntoObject(DatabaseMapping.java:1283)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildAttributesIntoObject(ObjectBuilder.java:342)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:717)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:504)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:454)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.buildObject(ObjectLevelReadQuery.java:723)
at org.eclipse.persistence.queries.ReadObjectQuery.executeObjectLevelReadQuery(ReadObjectQuery.java:448)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeDatabaseQuery(ObjectLevelReadQuery.java:1076)
at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:740)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.execute(ObjectLevelReadQuery.java:1036)
at org.eclipse.persistence.queries.ReadObjectQuery.execute(ReadObjectQuery.java:407)
at org.eclipse.persistence.internal.sessions.AbstractSession.internalExecuteQuery(AbstractSession.java:2392)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1291)
at org.eclipse.persistence.internal.sessions.AbstractSession.executeQuery(AbstractSession.java:1273)
at org.eclipse.persistence.internal.indirection.NoIndirectionPolicy.valueFromQuery(NoIndirectionPolicy.java:309)
at org.eclipse.persistence.mappings.ForeignReferenceMapping.valueFromRowInternal(ForeignReferenceMapping.java:1850)
at org.eclipse.persistence.mappings.OneToOneMapping.valueFromRowInternal(OneToOneMapping.java:1623)
at org.eclipse.persistence.mappings.ForeignReferenceMapping.valueFromRow(ForeignReferenceMapping.java:1739)
at org.eclipse.persistence.mappings.DatabaseMapping.readFromRowIntoObject(DatabaseMapping.java:1283)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildAttributesIntoObject(ObjectBuilder.java:342)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:717)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:504)
at org.eclipse.persistence.internal.descriptors.ObjectBuilder.buildObject(ObjectBuilder.java:454)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.buildObject(ObjectLevelReadQuery.java:723)
at org.eclipse.persistence.queries.ReadObjectQuery.executeObjectLevelReadQuery(ReadObjectQuery.java:448)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.executeDatabaseQuery(ObjectLevelReadQuery.java:1076)
at org.eclipse.persistence.queries.DatabaseQuery.execute(DatabaseQuery.java:740)

Answer 1

I assume you have set your cache-type to NONE and have a relationship cycle that does not use LAZY.

Do not set your cache-type to NONE, this is not how you disable the shared cache. cache-type of NONE if for only very special cases.

To disable the shared cache use,

<property name="eclipselink.cache.shared.default" value="false"/>

See,
http://wiki.eclipse.org/EclipseLink/FAQ/How_to_disable_the_shared_cache%3F