I solved this issue,
in persistence.xml I had : <mapping-file>META-INF/ProcessInstanceInfo.hbm.xml</mapping-file>
and I added the ProcessInstanceInfo.hbm.xml file in the same place as persistence.xml.
what I did'nt know jbpm-persistence-jpa-5.3.0.Final.jar comes with it's oun ProcessInstanceInfo.hbm.xml file,
So by changing the name of the file ProcessInstanceInfo.hbm.xml to (ProcessInstanceInfo_P.hbm.xml) in the folder META-INF of my project
and adding <mapping-file>META-INF/ProcessInstanceInfo_P.hbm.xml</mapping-file> (remove the old one) in my persistence.xml
and changing in ProcessInstanceInfo_P.hbm.xml file:
<property name="processInstanceByteArray" type="org.jbpm.persistence.processinstance.BlobUserType"
column="processInstanceByteArray" access="field" length="2147483647" />
to
<property name="processInstanceByteArray" type="org.hibernate.type.PrimitiveByteArrayBlobType" access="field" >
<column name="processInstanceByteArray" sql-type="oid"/>
</property>
this fix my issue
HTH