parent package class accessible from child packge class in java?

Question

In java parent package class accessible from child packge class? please explain me any one?

example package A.A1.A2 contains class sub package A contains class sup

Answer 1

In object of a.b.c.SomeOtherClass:

List<String> tmp=new ArrayList<String>(Arrays.asList(this.getClass().getPackage().getName().split("\\.")));
tmp.remove(tmp.size()-1);
String parent_package_name=tmp.toString().replace(", ", ".").replaceAll("[\\[\\]]", "");
Class cls=Class.forName(parent_package_name+".SomeClass");

Answer 2

Simply import it:

import A.sup;

Answer 3

In java parent package class accessible from child packge class? please explain me any one?

Not the way you're thinking. The directories are hierarchical, but the packages are just distinguishing names.

If a child needs a parent package, or any other outside its hierarchy, it simply needs to import it.

That's why import foo.* doesn't give you access to all sub-package names - packages aren't hierarchical the way directories are.

Answer 4

default class can be only used within package except subpackage

Answer 5

All answers seem to miss OP's point on package class as everyone seem to suggest importing the class as a workaround.

The answer is: package-level classes (i.e., without explicit access level modifier), are visible ONLY for the EXACT same package.

https://docs.oracle.com/javase/tutorial/java/javaOO/accesscontrol.html

If a class has no modifier (the default, also known as package-private), it is visible only within its own package

This effectively means that neither parent/child/external packages can view the class.

Answer 6

Java does not recognize the notion of a subpackage¹. As far as Java is concerned packages a and a.b and a.b.c are unrelated. They are just names.

So, if you want to access a.b.SomeClass from a.b.c.SomeOtherClass, you must either use a fully qualified class name, or add an import to SomeOtherClass

^{1 - From Java 9 onwards you can use modules to implement abstraction boundaries that are larger than a single package. This doesn't address this question which is about package-private access, but it could be viewed as an alternative to package-private.}

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As for your example that doesn't compile, I think we need a proper MCVE to understand that. My guess is that you have gotten the file organization for your source tree wrong ...

It is also possible that the problem is that the visibility of the class you are trying to import is wrong (package private), but that wouldn't cause the compiler to say that the package doesn't exist, like you said it does.