我搞不懂mysql的语法错误。
我在eclipse中的java程序中运行log-in screen，得到以下错误消息：
com.mysql.jdbc.exceptions.mysqlsyntaxerrorexception:您的sql语法有错误；查看与您的mysql服务器版本对应的手册，以获得使用near的正确语法[c@f8d6792“”在第1行
后面的7个字符 C@ 每次运行程序并引发异常时都进行更改。我试着看手册，但过了一会儿就泄气了。
以下是引发异常的部分的代码：

Connection conn = null;
String dbName = "test";
String serverip = "localhost";
String serverport = "3306";
String url = "jdbc:mysql://" + serverip + ":" + serverport + "/" + dbName;
String driver = "com.mysql.jdbc.Driver";
String databaseUserName = "root";
String databasePassword = "Pitbu!1s";
Statement stmt = null;
ResultSet rs = null;
String sql = "select * from users where user_name = '" + textField_UserName.getText() + " AND password = '" + passwordField_Password.getPassword().toString() + "'";

try {
  Class.forName(driver);
  conn = DriverManager.getConnection(url, databaseUserName, databasePassword);
  stmt = conn.createStatement();
  rs = stmt.executeQuery(sql);

  if (rs.next())

    lblUserName_Label.setText(textField_UserName.getText());
  lblUserNameOver_Label.setText(textField_UserName.getText() + "'s");
  textField_UserName.setText("");
  passwordField_Password.setText("");
  panel_Main.setVisible(true);
  panel_LogIn.setVisible(false);

  conn.close();
} catch (Exception i) {
  System.out.print(i);
}