Question

class User {

public static void main(String arg[]) throws SQLException {
    Connection con = DBConnect.getConnection();
    con.setAutoCommit(false);
    PreparedStatement pstmt;
    System.out.println(con.getMetaData().supportsSavepoints()); // true
    try {
        pstmt = con.prepareStatement("insert into emp(emp_id, emp_name, salary, address, contact_number)values(?,?,?,?,?)");
        pstmt.setInt(1, 1);
        pstmt.setString(2, "a");
        pstmt.setDouble(3, 8);
        pstmt.setString(4, "s");
        pstmt.setInt(5, 9);
        pstmt.executeUpdate();
        con.commit();
        Savepoint sp = con.setSavepoint();
        if (myMethod(con)) {
            /**
             * I want to rollback the nested transaction if any error occur
             */
            con.rollback(sp);
        }
    } catch (SQLException e) {
        e.printStackTrace();
    }
}

public static boolean myMethod(Connection con) throws SQLException {

    PreparedStatement pstmt;
    try {
        pstmt = con.prepareStatement("insert into emp(emp_id, emp_name, salary, address, contact_number)values(?,?,?,?,?)");
        pstmt.setInt(1, 2);
        pstmt.setString(2, "G");
        pstmt.setDouble(3, 8);
        pstmt.setString(4, "G");
        pstmt.setInt(5, 10);
        pstmt.executeUpdate();
        con.commit();
    } catch (SQLException e) {
        e.printStackTrace();
    }
    return true;
}

}

In the above code I want to rollback the nested transaction if any condition would fail . I have created a savepoint just after committing first transaction.I am getting an exception

java.sql.SQLException: SAVEPOINT _667166fe_13ab4b3e3de__8000 does not exist
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:2928)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:1571)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:1666)
at com.mysql.jdbc.Connection.execSQL(Connection.java:2988)
at com.mysql.jdbc.Statement.executeUpdate(Statement.java:935)
at com.mysql.jdbc.Statement.executeUpdate(Statement.java:873)
at com.mysql.jdbc.Connection.rollback(Connection.java:4777)
at com.User.main(User.java:31)

I would like to know whether the nested transaction will rollback or not ?

Answer 1

Since you are already calling con.commit(); before and after(in myMethod() method) Savepoint sp = con.setSavepoint();, there is no savepoint and hence complaining.

COMMIT removes all the save points. Please refer documentation here:

1. Oracle SAVEPOINT Statement
2. SQLite Save Point

Please remove the commit call, if you want to set a save point.

In the current state of your code, there is no rollback possible as all transactions are committed, if successful.