JBuilder一个问题

[yzj123]

不知道什么原因，原来好好的程序。现在突然连import等最基本的东西都不认了，下面划了好多红色波浪线。
行的左边还有惊叹号。


我在网上查了查，没查到什么原因。
哪位高手能告诉我，该如何解决。
多谢了，在线等！

[阁楼上的伟哥]

好久没有用JBuilder了。
顶一下……

[大_爱]

你先保存一下，看有没有错，或者运行哈，看报什么错误

[yzj123]

error ：0
但是命令台上显示好多红色字体
"HelloWorldClass.java": package javax.swing does not exist at line 3, column 20
"HelloWorldClass.java": package java.awt does not exist at line 4, column 1
"HelloWorldFrame.java": package java.awt does not exist at line 3, column 1
"HelloWorldFrame.java": package java.awt.event does not exist at line 4, column 1
"HelloWorldFrame.java": package javax.swing does not exist at line 5, column 1
"HelloWorldFrame.java": package javax.swing.border does not exist at line 6, column 1
"HelloWorldFrame.java": cannot resolve symbol: class JFrame in class newhelloworld.HelloWorldFrame at line 17, column 38
"HelloWorldFrame.java": cannot resolve symbol: class JPanel in class newhelloworld.HelloWorldFrame at line 18, column 3
"HelloWorldFrame.java": cannot resolve symbol: class JMenuBar in class newhelloworld.HelloWorldFrame at line 19, column 3
"HelloWorldFrame.java": cannot resolve symbol: class JMenu in class newhelloworld.HelloWorldFrame at line 20, column 3
"HelloWorldFrame.java": cannot resolve symbol: class JMenuItem in class newhelloworld.HelloWorldFrame at line 21, column 3
"HelloWorldFrame.java": cannot resolve symbol: class JMenu in class newhelloworld.HelloWorldFrame at line 22, column 3