My question was not fully answered 
I have analysed and found this behaviour is normal and as per the design. Have a look at the below link: and look for Update Counts in the Oracle Implementation of Standard Batching
It says
“For a prepared statement batch, it is not possible to know the number of rows affected in the database by each individual statement in the batch. Therefore, all array elements have a value of -2. According to the JDBC 2.0 specification, a value of -2 indicates that the operation was successful but the number of rows affected is unknown.”
http://docs.oracle.com/cd/E11882_01/java.112/e16548/oraperf.htm#JJDBC28757
#Adapters-and-E-Standards#Integration-Server-and-ESB#webMethods