I get a Open Connection Exception while trying to invoke beginTransaction().

Details are given below:

Hibernate version: 3.2

Mapping documents:

<hibernate-configuration>

<session-factory>

<!-- Database connection settings -->
<property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
<property name="connection.url">jdbc:oracle:oci:@xxx</property>
<property name="connection.username">abc</property>
<property name="connection.password">abc</property>

<!-- configuration pool via c3p0-->
<property name="c3p0.acquire_increment">1</property>
<property name="c3p0.idle_test_period">100</property> <!-- seconds -->
<property name="c3p0.max_size">100</property>
<property name="c3p0.max_statements">0</property>
<property name="c3p0.min_size">5</property>
<property name="c3p0.timeout">100</property> <!-- seconds -->

<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">2</property>

<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.OracleDialect</property>

<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>

<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>

<!-- Echo all executed SQL to stdout -->
<property name="show_sql">false</property>

<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">validate</property>

<mapping resource="some.hbm.xml"/>

</session-factory>

</hibernate-configuration>

Code between sessionFactory.openSession() and session.close():

Session s = factory.openSession();
Transaction tx=null;
Object result = null;

try {
tx = s.beginTransaction();
List resultList = s.createCriteria(DBCacheStore.class).add(Expression.eq("key", key)).list();
if(resultList != null && resultList.size() > 0) {
DBCacheStore store = (DBCacheStore)resultList.get(0);
return store;
}
tx.commit();

return null;
} catch(Exception e) {
e.printStackTrace();
if (tx != null) tx.rollback();
throw new DBCacheException(e.getMessage());
} finally {
s.close();
}


Full stack trace of any exception that occurs:


org.hibernate.exception.GenericJDBCException: Cannot open connection
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:103)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:91)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)
at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java(Compiled Code))
at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java(Inlined Compiled Code))
at org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java(Compiled Code))
at org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java(Compiled Code))
at org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java(Compiled Code))
at com.xxx.cache.DBCache.getDBCacheStore(DBCache.java(Compiled Code))
at com.xxx.cache.DBCache.get(DBCache.java(Compiled Code))
at com.xxx.cache.ProfileCache.get(ProfileCache.java(Compiled Code))
at com.xxx.aggregator.ExecutionTree.ExecuteSearch(ExecutionTree.java(Compiled Code))
at com.xxx.service.SearchRequestHandler.Execute(SearchRequestHandler.java(Compiled Code))
at com.xxx.service.RequestHandler.Execute(RequestHandler.java(Compiled Code))
at com.xxx.core.RunnableRequest.run(RunnableRequest.java(Compiled Code))
at com.xxx.core.AtAThread.run(AtAThread.java(Compiled Code))
Caused by: java.sql.SQLException: Connections could not be acquired from the underlying database!
at com.mchange.v2.sql.SqlUtils.toSQLException(SqlUtils.java:106)
at com.mchange.v2.c3p0.impl.C3P0PooledConnectionPool.checkoutPooledConnection(C3P0PooledConnectionPool.java(Inlined Compiled Code))
at com.mchange.v2.c3p0.impl.AbstractPoolBackedDataSource.getConnection(AbstractPoolBackedDataSource.java(Compiled Code))
at org.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java(Compiled Code))
... 13 more
Caused by: com.mchange.v2.resourcepool.CannotAcquireResourceException: A ResourcePool could not acquire a resource from its primary factory or source.
at com.mchange.v2.resourcepool.BasicResourcePool.awaitAvailable(BasicResourcePool.java:1319)
at com.mchange.v2.resourcepool.BasicResourcePool.prelimCheckoutResource(BasicResourcePool.java(Compiled Code))
at com.mchange.v2.resourcepool.BasicResourcePool.checkoutResource(BasicResourcePool.java(Compiled Code))
... 16 more


Name and version of the database you are using: Oracle 9i

The generated SQL (show_sql=true): false

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