Connection pooling is not working for salesforce resource-adapter

<resource-adapter id="salesforcefour" statistics-enabled="true">
                    <module slot="main" id="org.jboss.teiid.resource-adapter.salesforce-41"/>
                    <connection-definitions>
                        <connection-definition class-name="org.teiid.resource.adapter.salesforce.SalesForceManagedConnectionFactory" jndi-name="java:/sfDS41" enabled="true" connectable="true" use-java-context="true" pool-name="sfDS41">
                            <config-property name="connectTimeout">30000</config-property>
                            <config-property name="password"></config-property>
                            <config-property name="URL">https://test.salesforce.com/services/Soap/u/45.0</config-property>
                            <config-property name="requestTimeout">120000</config-property>
                            <config-property name="username"></config-property>
                            <pool>
                                <min-pool-size>5</min-pool-size>
                                <initial-pool-size>5</initial-pool-size>
                                <prefill>true</prefill>
                                <use-strict-min>true</use-strict-min>
                                <flush-strategy>FailingConnectionOnly</flush-strategy>
                            </pool>
                        </connection-definition>
                    </connection-definitions>
                </resource-adapter>

sudo netstat -nlpat|grep java

tcp        0      0 127.0.0.1:31000         0.0.0.0:*               LISTEN      27430/java          
tcp        0      0 127.0.0.1:8443          0.0.0.0:*               LISTEN      27430/java          
tcp        0      0 127.0.0.1:9990          0.0.0.0:*               LISTEN      27430/java          
tcp        0      0 127.0.0.1:35432         0.0.0.0:*               LISTEN      27430/java          
tcp        0      0 127.0.0.1:8080          0.0.0.0:*               LISTEN      27430/java          
tcp        0      0 127.0.0.1:31000         127.0.0.1:51860         ESTABLISHED 27430/java          
tcp        0      0 127.0.0.1:31000         127.0.0.1:51858         ESTABLISHED 27430/java          
tcp        0      0 127.0.0.1:9990          127.0.0.1:60048         ESTABLISHED 27430/java