Mam problem z Hibernate (hibernate-core-4.1.9.Final.jar)

Kiedy testuję hibernację w pętli for wszystko działa dobrze:

for(int i=0;i<1500;i++){

    UserDAO.getInstance.getById(1);
}

Kiedy dodamThread.sleep () w pętli for

 for(int i=0;i<1500;i++){


        UserDAO.getInstance.getById(1);
        Thread.sleep(60000);
 }

Po 1 minucie otrzymuję wyjątek:

00:20:06,447  WARN SqlExceptionHelper:143 - SQL Error: 0, SQLState: 08S01
00:20:06,448 ERROR SqlExceptionHelper:144 - Communications link failure

The last packet successfully received from the server was 120,017 milliseconds ago.  The last packet sent successfully to the server was 9 milliseconds ago.
Exception in thread "main" org.hibernate.exception.JDBCConnectionException: Communications link failure

The last packet successfully received from the server was 120,017 milliseconds ago.  The last packet sent successfully to the server was 9 milliseconds ago.
    at org.hibernate.exception.internal.SQLStateConversionDelegate.convert(SQLStateConversionDelegate.java:131)
    at org.hibernate.exception.internal.StandardSQLExceptionConverter.convert(StandardSQLExceptionConverter.java:49)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:125)
    at org.hibernate.engine.jdbc.spi.SqlExceptionHelper.convert(SqlExceptionHelper.java:110)
    at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:129)
    at org.hibernate.engine.jdbc.internal.proxy.AbstractProxyHandler.invoke(AbstractProxyHandler.java:81)
    at sun.proxy.$Proxy11.executeQuery(Unknown Source)
    at org.hibernate.loader.Loader.getResultSet(Loader.java:2031)
    at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1832)
    at org.hibernate.loader.Loader.executeQueryStatement(Loader.java:1811)
    at org.hibernate.loader.Loader.doQuery(Loader.java:899)
    at org.hibernate.loader.Loader.doQueryAndInitializeNonLazyCollections(Loader.java:341)
    at org.hibernate.loader.Loader.doList(Loader.java:2516)
    at org.hibernate.loader.Loader.doList(Loader.java:2502)
    at org.hibernate.loader.Loader.listIgnoreQueryCache(Loader.java:2332)
    at org.hibernate.loader.Loader.list(Loader.java:2327)
    at org.hibernate.loader.criteria.CriteriaLoader.list(CriteriaLoader.java:124)
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1621)
    at org.hibernate.internal.CriteriaImpl.list(CriteriaImpl.java:374)
    at org.hibernate.internal.CriteriaImpl.uniqueResult(CriteriaImpl.java:396)
    at com.fit.utilities.BaseDAO.getById(BaseDAO.java:35)
    at com.fit.test.Testiranje.main(Testiranje.java:51)
Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure

The last packet successfully received from the server was 120,017 milliseconds ago.  The last packet sent successfully to the server was 9 milliseconds ago.
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
    at java.lang.reflect.Constructor.newInstance(Unknown Source)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1121)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3603)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3492)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4043)
    at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2503)
    at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2664)
    at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2815)
    at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155)
    at com.mysql.jdbc.PreparedStatement.executeQuery(PreparedStatement.java:2322)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.hibernate.engine.jdbc.internal.proxy.AbstractStatementProxyHandler.continueInvocation(AbstractStatementProxyHandler.java:122)
    ... 17 more
Caused by: java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
    at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3052)
    at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3503)
    ... 29 more

Tutaj jest mójhibernate.cfg.xml

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
          "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
          "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

    <session-factory>


         <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
          <property name="connection.url">jdbc:mysql://xxxxxx:3306/xxxx</property>
          <property name="connection.username">xxxx</property>
          <property name="connection.password">xxxx</property>
          <property name="dialect">org.hibernate.dialect.MySQLDialect</property>
          <property name="hibernate.hbm2ddl.auto">update</property>
          <property    name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
          <property name="show_sql">false</property>
          <property name="hibernate.connection.pool_size">1</property>





         <!-- Mapping files -->
        <mapping class="com.xxx.model.xxxxx" />
        <mapping class="com.xxx.model.xxxxx" />
        <mapping class="com.xxx.model.xxxxx" />

    </session-factory>
</hibernate-configuration> 

Jak rozwiązać ten problem?

AKTUALIZACJA: Myślę, że rozwiązuję problem.

Umieściłem to w hibernate.cfg.xml

 <!-- 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">10</property> 
<property name="c3p0.timeout">100</property> <!-- seconds -->