Make sure you are closing all opened connection  after using it. To find out the connection leak use the following parameters for connection pooling

<parameter> <name>removeAbandoned</name> <value>true</value> </parameter>
<parameter>
<name>removeAbandonedTimeout</name>
<value>60</value>
</parameter>
<parameter>
<name>logAbandoned</name>
<value>true</value>
</parameter>