connexion tomcat interrompue après une période d'inactivité

J'ai résolu ce problème en utilisant c3p0 pool de connexion

<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
        destroy-method="close" p:driverClass="${jdbc.driverClassName}"
        p:jdbcUrl="${jdbc.url}" p:user="${jdbc.username}" p:password="${jdbc.password}"
        p:preferredTestQuery="select 1 from dual" p:idleConnectionTestPeriod="300"
        p:maxStatements="100" p:acquireRetryAttempts="1" p:checkoutTimeout="1000"
        p:testConnectionOnCheckout="true" p:testConnectionOnCheckin="true"
        p:acquireIncrement="${c3p0.acquire_increment}" p:minPoolSize="${c3p0.min_size}"
        p:maxPoolSize="${c3p0.max_size}" p:maxIdleTime="${c3p0.max_idle_time}"

        p:unreturnedConnectionTimeout="${c3p0.unreturned_connection_timeout}" />

le fichier DB.properties :

#hibernate
hibernate.dialect=org.hibernate.dialect.OracleDialect
hibernate.hbm2ddl.auto= update
hibernate.connection.autocommit = true
hibernate.cache = true
hibernate.query.cache = true
hibernate.statistics = true
hibernate.c3p0.idle_test_period=300
#c3p0 pool
c3p0.acquire_increment=5
c3p0.max_size=100
c3p0.min_size=5
c3p0.max_idle_time=1200
c3p0.unreturned_connection_timeout=120