子包之间的Java私有类

Question

My Java library is made of a few sub-packages (com.example.lib.api, com.example.lib.imp, com.example.lib.util,...).

The classes in api use classes A and B from imp . The classes in imp use class C in util . I am forced to make A , B and C public, but I don't want them to be exposed to users of my library. Not hiding anything, my library is open source, but minimal APIs are simpler to understand.

Is there a way around it?

Answer 1

In Java 9 you will be able to control which packages are exported from a JAR. This way you can make them public, but not available to anyone else.

For now you can't control this. You either put everything in one package or rely on the documentation to make it clear they should not be used. eg jdk.internal assumes no one should use these except the JDK.

Answer 2

You cannot use a private class in any other package . Instead the class can be made public and the methods and variables can be made protected . So in this case the classes can be extended where they need and the contents in the class can be accessed only by the sub classes which extended it.