How to create Postgrest DB connection using resouce.properties?

Issue

• Getting error while configuring resource.properties for PostgreSQL DB. Following is exception stack trace.

WARNING: unable to create resource with unique name jdbc/jbpm
bitronix.tm.resource.ResourceConfigurationException: cannot create JDBC datasource named jdbc/jbpm
    at bitronix.tm.resource.jdbc.PoolingDataSource.init(PoolingDataSource.java:92)
...
Caused by: bitronix.tm.utils.PropertyException: no writeable property 'URL' in class 'org.postgresql.xa.PGXADataSource'
    at bitronix.tm.utils.PropertyUtils.getSetter(PropertyUtils.java:318)
    at bitronix.tm.utils.PropertyUtils.setDirectProperty(PropertyUtils.java:217)

• Following are the entries of resource.properties

resource.ds1.className=org.postgresql.xa.PGXADataSource
resource.ds1.uniqueName=jdbc/jbpm
resource.ds1.minPoolSize=0
resource.ds1.maxPoolSize=10
resource.ds1.driverProperties.URL=jdbc:postgresql://localhost:5432/bpms
resource.ds1.driverProperties.user=bpms
resource.ds1.driverProperties.password=bpms
resource.ds1.allowLocalTransactions=true