Locks are not released when executing SQL Select on AS400/DB2, using IBM Toolbox for Java (JDBC Driver)

Hello,
I am a java programmer and I am using AS400/DB2 database.
In order to connect to the database I am using IBM Toolbox for Java (JTOpen version 6 and I try also version 7.3).
It seems that executing the same SQL select more than once, with the same connection, keeps locks on records from the result set, even if the Statement or ResultSet objects are closed.
The problem occurs both with connection that was created by DriverManager and connection that was taken form Connection pool.


Description:
When using IBM Toolbox for Java to execute SQL select statements, a job named QZDASOINIT is created with a shared lock on the record/file.
When the Statement (that executes the SQL select) is closed (or the ResultSet object is closed) the job QZDASOINIT should be ended.

A test shows that when we executes SQL select once and then close the Statement object (or the ResultSet object), it cause the job QZDASOINIT to be ended.
When we try to execute the exactly same SQL select with the same connection, then close the Statement object, the job QZDASOINIT is remaining and the shared lock is also remaining.
When we close the connection the all the jobs (QZDASOINIT) that were created using this connection are ended and the locks are free.

For instance, if we execute 2 different SQL select with the same connection, say A and B
1. execute the A sql select (cause QZDASOINIT job to be created with shared lock)
2. closing the Statement object (cause to end the job and release the lock)
3. execute the B sql select (cause QZDASOINIT job to be created with shared lock)
4. closing the Statement object (cause to end the job and release the lock)
5. execute the A sql select again (cause QZDASOINIT job to be created with shared lock)
6. closing the Statement object (The job is NOT ended and the lock is still exists)
7. execute the B sql select again (cause QZDASOINIT job to be created with shared lock)
8. closing the Statement object (The job is NOT ended and the lock is still exists)

Now 2 locks are exists
For each SQL Select the executes more than once with the same connection, the job QZDASOINIT) and the lock are not released.


The parameters that I try to use with the connection are:
Key

Value

xa loosely coupled support

0

transaction isolation

read uncommited





cursor hold

false

rollback cursor hold

false

cursor sensitivity

asensitive

lazy close

False





block criteria

0

data compression

false

extended dynamic

false

prefetch

false

hold input locators

false

hold statements

false





trace

true



// The code for getting the connection:
Connection connection = null;

// Initiate connection properties
java.util.Properties prop = new java.util.Properties();
prop.put("user", dbUser);
prop.put("password", dbPassword);
prop.put("xa loosely coupled support", "0");
prop.put("transaction isolation", "read uncommited");
prop.put("cursor hold", "false");
prop.put("rollback cursor hold", "false");
prop.put("hold input locators", "false");
prop.put("hold statements", "false");
. . .

prop.put("trace", "true");

connection = DriverManager.getConnection(dbURL, prop);
connection.setAutoCommit(true);
connection.setTransactionIsolation(Connection.TRANSACTION_READ_UNCOMMITTED)connection.setHoldability(ResultSet.CLOSE_CURSORS_AT_COMMIT);


// The code to exeute SQL Statment:
String sql = "SELECT * FROM MYLIB.MYFILE";
Statement stmnt = connection.createStatement();
ResultSet rs = stmnt.executeQuery(sql);
// ---- Now the job QZDASOINIT is create with shared lock
. . .
rs.next();

stmnt.close();
// ---- Now the job QZDASOINIT is ended

stmnt = connection.createStatement();
rs = stmnt.executeQuery(sql);
// ---- Now the job QZDASOINIT is create again with shared lock
. . .
rs.next();

stmnt.close();
// ---- Now the job QZDASOINIT is still remaining with shared lock




Thanks,
Tomer S.