java中的错误解决！！！急急急.....

源代码：import acm.program.*;

public class HelloProgram extends ConsoleProgram {

public void run() {
println("hello, world");
}



public static void main(String[] args) {
new HelloProgram().start(args);
}
}
错误提示：

at java.lang.Class.newInstance(Unknown Source)
at sun.applet.AppletPanel.createApplet(Unknown Source)
at sun.applet.AppletPanel.runLoader(Unknown Source)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
import acm.graphics.*;
import acm.program.*;

public class HelloProgram extends GraphicsProgram{
public void run() {
add(new GLabel("Hello,World",0,0));
}
}
这个程序也不行，错误提示一样
at java.lang.Class.newInstance(Unknown Source)
at sun.applet.AppletPanel.createApplet(Unknown Source)
at sun.applet.AppletPanel.runLoader(Unknown Source)
at sun.applet.AppletPanel.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

你继承了Thread或者实现Runable了吗？

辅导费

类格式化错误，你看一下你的开发环境的jdk版本是不是比tomcat所指向的jdk版本高，如果是的话改一下

new HelloProgram().start(args);改成下面的： HelloProgram hp = new HelloProgram(); hp.start(); 看看行不行