A JDBC connection is created in auto-commit mode by default. This means that each individual SQL statement is treated as a transaction and will be automatically committed as soon as it is executed. If you require two or more statements to be grouped into a transaction then you need to disable auto-commit mode using below command.
con.setAutoCommit(false);
Once auto-commit mode is disabled, no SQL statements will be committed until you explicitly call the commit method. A Simple transaction with use of autocommit flag is demonstrated below.
con.setAutoCommit(false);
PreparedStatement updateStmt =
con.prepareStatement( “UPDATE EMPLOYEE SET SALARY = ? WHERE EMP_NAME LIKE ?”);
updateStmt.setInt(1, 5000); updateSales.setString(2, “Jack”);
updateStmt.executeUpdate();
updateStmt.setInt(1, 6000); updateSales.setString(2, “Tom”);
updateStmt.executeUpdate();
con.commit();
con.setAutoCommit(true);