I am getting the following exception when several threads are trying to do a select to the same table at the same time:

org.hibernate.exception.GenericJDBCException: could not load an entity:

Complete trace:

com.ncs.dao.ChDAO - get failed
org.hibernate.exception.GenericJDBCException: could not load an entity: [com.ncs.entity.Ch#25]
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:126)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:114)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:66)
at org.hibernate.loader.Loader.loadEntity(Loader.java:1895)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:71)
at org.hibernate.loader.entity.AbstractEntityLoader.load(AbstractEntityLoader.java:65)
at org.hibernate.persister.entity.AbstractEntityPersister.load(AbstractEntityPersister.java:3072)
at org.hibernate.event.def.DefaultLoadEventListener.loadFromDatasource(DefaultLoadEventListener.java:434)
at org.hibernate.event.def.DefaultLoadEventListener.doLoad(DefaultLoadEventListener.java:415)
at org.hibernate.event.def.DefaultLoadEventListener.load(DefaultLoadEventListener.java:165)
at org.hibernate.event.def.DefaultLoadEventListener.proxyOrLoad(DefaultLoadEventListener.java:223)
at org.hibernate.event.def.DefaultLoadEventListener.onLoad(DefaultLoadEventListener.java:126)
at org.hibernate.impl.SessionImpl.fireLoad(SessionImpl.java:905)
at org.hibernate.impl.SessionImpl.get(SessionImpl.java:842)
at com.ncs.dao.ChDAO.findById(Unknown Source)
at com.ncs.ln.ChManagement.getChById(Unknown Source)
at com.ncs.ctrl.CtrlEventProcess.execute(Unknown Source)
at com.ncs.comm.ChMessageServiceThread.eventProcess(Unknown Source)
at com.ncs.comm.ChMessageServiceThread.chMessageFrameProcess(Unknown Source)
at com.ncs.comm.ChMessageServiceThread.processChMessage(Unknown Source)
at com.ncs.comm.ChMessageService.run(Unknown Source)
Caused by: org.postgresql.util.PSQLException: ERROR: current transaction is aborted, commands ignored until end of transaction block
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:1559)
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1327)
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:193)
at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:452)
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:351)
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeQuery(AbstractJdbc2Statement.java:255)
at org.hibernate.jdbc.AbstractBatcher.getResultSet(AbstractBatcher.java:208)
at org.hibernate.loader.Loader.getResultSet(Loader.java:1808)
at org.hibernate.loader.Loader.doQuery(Loader.java:697)
at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:259)
at org.hibernate.loader.Loader.loadEntity(Loader.java:1881)
... 17 more

I would like to know if it is a problem with hibernate configuration:

<property name="connection.username">postgres</property>
<property name="connection.url">jdbc:postgresql://localhost:5432/test</property>
<property name="dialect">org.hibernate.dialect.PostgreSQLDialect</property>
<property name="connection.password">12345</property>
<property name="connection.driver_class">org.postgresql.Driver</property>

<!-- configuration pool via c3p0-->
<property name="c3p0.acquire_increment">2</property>
<property name="c3p0.idle_test_period">100</property> <!-- seconds -->
<property name="c3p0.max_size">100</property>
<property name="c3p0.max_statements">50</property>
<property name="c3p0.min_size">5</property>
<property name="c3p0.timeout">300</property> <!-- seconds -->
<property name="c3p0.idle_test_period">300</property> <!-- seconds -->

Or a PostgreSQL configuration problem

Thanks in advance,