Not closing ResultSet, but not getting ORA-01000

Question

I have an application that is generating the familiar ORA-01000 error.
Whilst investigating the problem, I wrote a small test program. In the test program I tried to get the ORA-01000, but I don't get it (has anyone ever complained about not getting ORA-01000 before?!)
connection = DriverManager.getConnection("<connection string>");
String sql = "SELECT c1 FROM pdtab2 WHERE Id>=? AND Id<=?";
PreparedStatement ps = connection.prepareStatement(sql);
for (int i = 1; i <= 30000; ++i)
    ps.setInt(1, i-1);
    ps.setInt(2, i+1);
    if (i % 100 == 0)
        System.out.println("i=" +i);
        System.out.println("getCurrentOpenCursors(connection)="
                           +getCurrentOpenCursors(connection));
    try
        rs = ps.executeQuery();
        while (rs.next())
            result = rs.getInt(1);
    catch (SQLException e2)
        e2.printStackTrace();
    finally
        // Do nothing! Do not close the result set
}getCurrentOpenCursors does:
select count(*) AS COUNT from v$open_cursor where user_name like 'me'
I have reduced OPEN_CURSORS down from 300 to 100, but getCurrentOpenCursors always returns less that what it is set to. Suggesting that OPEN_CUSRORS is not a limit, but rather a pool size?
The result set returns more than one record, I never close the result set, yet I do not get an ORA-01000 error. I have tried auto-commit true and false on the connection. Is the prepared statement closing its previous result set on each new iteration of the loop, hence stopping me getting a problem?
I am using Oracle version 10.2.0.1, the corresponding ojdbc14.jar, and Java 1.4.
Thanks,
Paul

Answer 1

Here is a program that does that for you.
To fix the program, un-comment the line 24 of the code and run again.
C:\> type TestCursors.java
import java.lang.* ;
import java.util.* ;
import java.sql.* ;
import oracle.jdbc.* ;
public class TestCursors
    public static void main(String[] args) throws SQLException, ClassNotFoundException
        Class.forName("oracle.jdbc.driver.OracleDriver");
        Connection connection = DriverManager.getConnection("jdbc:oracle:oci:@localhost:1521:ORCL");
        ResultSet rs ;
        PreparedStatement ps ;
        for (int i = 1; i <= 30000; ++i)
            String sql = "SELECT 20 FROM scott.emp WHERE deptno = ?";
            ps = connection.prepareStatement(sql);
            ps.setInt(1, 10);
            try
                rs = ps.executeQuery();
                rs.close() ;
                //ps.close() ;
            catch (SQLException e2)
                System.out.println("The value if i is " + i) ;
                throw e2 ;
C:\> javac TestCursors.java
C:\> java TestCursors
The value if i is 301
Exception in thread "main" java.sql.SQLException: ORA-01000: maximum open cursors exceeded
        at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:111)
        at oracle.jdbc.driver.T2CConnection.checkError(T2CConnection.java:671)
        at oracle.jdbc.driver.T2CConnection.checkError(T2CConnection.java:597)
        at oracle.jdbc.driver.T2CPreparedStatement.executeForDescribe(T2CPreparedStatement.java:570)
        at oracle.jdbc.driver.OracleStatement.executeMaybeDescribe(OracleStatement.java:1030)
        at oracle.jdbc.driver.OracleStatement.doExecuteWithTimeout(OracleStatement.java:1123)
        at oracle.jdbc.driver.OraclePreparedStatement.executeInternal(OraclePreparedStatement.java:3284)
        at oracle.jdbc.driver.OraclePreparedStatement.executeQuery(OraclePreparedStatement.java:3328)
        at TestCursors.main(TestCursors.java:22)
C:\>