/*Login.java*/
public class LoginManager extends JFrame {
private JPanel contentPane;
private JTextField textField;
private JPasswordField passwordField;
ClientReceive recvThread;
String user1 = textField.getText();
String password1 = new String(passwordField.getPassword());
recvThread = new ClientReceive(user1,password1);
recvThread.start();


/*CheckMoney.java*/

public class CheckMoney extends Thread {
    JTextField username;
    JTextField password;
public CheckMoney(JTextField username, JTextField password){
        this.username = username;
        this.password = password;
/

------解决方案--------------------
呵呵呵，不好意思了，我也是正在做东西——聊天室，路过这里看见你的问题，就顺便看看了
我见我也用到这样的处理方式，所以就复制粘贴加修改发给你了，，，
Java code


/*Login.java*/
public class LoginManager extends JFrame {
private JPanel contentPane;
private JTextField textField;
private JPasswordField passwordField;
ClientReceive recvThread;
String user1 = textField.getText();
String password1 = new String(passwordField.getPassword());
recvThread = new CheckMoney(user1,password1);
recvThread.start();


/*CheckMoney.java*/

public class CheckMoney extends Thread {
    JTextField username;
    JTextField password;
public CheckMoney(JTextField username, JTextField password){
        this.username = username;
        this.password = password;
/

------解决方案--------------------
Thread是程序中的执行线程。Java 虚拟机允许应用程序并发地运行多个执行线程。  
start()是Thread下的函数
start()使该线程开始执行；Java 虚拟机调用该线程的 run 方法。

------解决方案--------------------
话说你的这句：String password1 = new String(passwordField.getPassword());

你是不是对密码那个文本字段处理过了啊？(比如说你输入密码的时候，显示回来的格式是 *******)
要是用户名，密码这两个文本字段都是明文的话，
那就改为：String password1 = pasawordtField.getText();

------解决方案--------------------
不过不管你处理没处理过，都改为：String password1 = pasawordtField.getText();试试吧，，，

------解决方案--------------------
我换了一种方法实现窗体间传参
Java code

   /*login.java*/
   static String username;
   static String password;
    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        CheckMoney temp;
        username = jTextField1.getText();
        password=String.valueOf(jPasswordField1.getPassword());
        temp = new CheckMoney(); //!! 把两个窗口联系起来
        temp.setVisible(true); //设置窗口2为可见 
        this.setVisible(false);//该窗口隐藏 
    } 

   /*CheckMoney.java*/   
   //按钮点击事件响应。
   private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        String str;
        str=jPasswordField.password;//从登陆窗体获取密码
        jTextField1.setText(str);   
    }