private void addToBatch(String sql) throws SQLException{
sttmnt.addBatch(sql);
batchSize++;
if (batchSize == elementsPerExecute){
    executeBatches();
}
}

try {
  connection con.setAutoCommit(false);
  PreparedStatement prepStmt = con.prepareStatement(
    "UPDATE DEPT SET MGRNO=? WHERE DEPTNO=?");
  prepStmt.setString(1,mgrnum1);
  prepStmt.setString(2,deptnum1);
  prepStmt.addBatch();

  prepStmt.setString(1,mgrnum2);
  prepStmt.setString(2,deptnum2);
  prepStmt.addBatch();
  int [] numUpdates=prepStmt.executeBatch();
  for (int i=0; i < numUpdates.length; i++) {
    if (numUpdates[i] == -2)
      System.out.println("Execution " + i +
        ": unknown number of rows updated");
    else
      System.out.println("Execution " + i +
        "successful: " numUpdates[i] + " rows updated");
  }
  con.commit();
} catch(BatchUpdateException b) {
  // process BatchUpdateException
}

Sring query = "INSERT INTO users (id, user_name, password) VALUES(?,?,?)";
PreparedStatement statement = connection.preparedStatement(query);
for(User user: userList){
    statement.setString(1, user.getId()); //1 is the first ? (1 based counting)
    statement.setString(2, user.getUserName());
    statement.setString(3, user.getPassword());
    statement.addBatch();
}

statement.executeBatch();
statement.clearBatch(); //If you want to add more,
//(so you don't do the same thing twice)