java - Intermittent state of executing multiple queries using a Statement object -

I am performing several SQL statements using single connections and statement objects as two processes.

Pre-Process (Preprocess. Java)

Post Processes (Post Processes. Java)

My procedure steps are as follows:

2. During performing the expected SQL statement using the statement object created during the pre-process.
3. Creating a Contribution Object and Set Auto Comit ()
4. Then I pass the same Statement Object and execute the required SQL Statement for the post process.
5. Finally close the transaction ( connection.commit (); ) and close Connection, Statement Objects.

My problem is this:

Sometimes the post execution statements are not reflected in the database that is, if I include any records in post-processing Or update, they are not available in the records database.

But post-process execution is working fine without exception.

The probability of this case is out of 1/5 (which means that I used to expect 4x work but its problematic 1 time).

Can anyone tell any problem?

I am using Jdk 1.7 and Postgresql version 9.3.