The declared package "" does not match the expected package

Today I started using Eclipse to learn Java, mainly because I feel that I already know the command line command line, each time to knock, to switch directories, compared to waste time.

And there's a lot of eclipse shortcuts, so much to forget.

And this eclipse is not as scary as it used to be, and I don't know why, maybe it's because of an Android development.

I do not know why I was afraid, seems to have encountered a lot of problems, it is estimated that the Java is also unfamiliar with the reasons.

Sun Weichen's book Java Object-oriented programming

Eclipse error detected when testing P47

The declared package "" does not match the expected package

To find out, a Web page said what the directory is not right, I do not know how to recall the package declaration statement

Sure enough, plus

Package Com.testPackage.hai;

Right away.