How can I know the classes of a given package

Question

Given a package in java language, I want to know how many classes it contains and their list (list of these classes).

I can access to my package with myClass1.class.getPackage() but after this I don't have some thing like getClasses() or size() or lenght or ClassesCount().

Thank You

You'll have to write your own classloader for that – svz Nov 23 '13 at 16:18 — svz, Nov 23 '13 at 16:18

score 1 · Answer 1 · answered Nov 23 '13 at 16:21

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In Java, classes are loaded dynamically. So there's simply no way to do what you're trying to do; the virtual machine itself does not know the full list of classes within a package.

answered Nov 23 '13 at 16:21

Jose Torres

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but when I am programming and I write `myPackage.` just after writing point(.) I have the list of all classes but not when I write `myClass.class,getPackage()` – RiadSaadi Nov 23 '13 at 16:24
Right. Your development environment knows what all the classes are; it has to, because it needs to compile them. But this information is not available to the program itself unless you explicitly put it in. – Jose Torres Nov 23 '13 at 16:29

score 1 · Answer 2 · edited May 23 '17 at 12:28

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There are already many questions and answers on this, you can follow these links

a) How to get all classes names in a package?

b) How can I list all classes loaded in a specific class loader

c) Can you find all classes in a package using reflection?

edited May 23 '17 at 12:28

Community

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answered Nov 23 '13 at 16:24

Santosh Joshi

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I am sorry, I saw the first one and the second one they are not exactly like mine, but the last one is. what to do? should I delete the question? – RiadSaadi Nov 23 '13 at 16:29
@RiadSaadi I think you should not delete there are already many useful expert comments in this post. – Santosh Joshi Nov 23 '13 at 16:33
@SantoshJoshi As you know that this is a duplicate of other questions so you should not post as answer. – Nov 23 '13 at 16:37
but in the reglementation, what to do in duplicate case? – RiadSaadi Nov 23 '13 at 16:41
@RiadSaadi, please, if you think that your question is a duplicate, go ahead and remove it. I am an answerer too, but I should not answer a question which has already complete answer somewhere else and better than mine. – Sage Nov 23 '13 at 16:41
@rocking, yes you are right, will take care of this. – Santosh Joshi Nov 23 '13 at 16:43
@SantoshJoshi There is a possibility of getting downvotes if you answer duplicate questions.So i just made you aware of it – Nov 23 '13 at 16:45

score 1 · Accepted Answer · answered Nov 23 '13 at 16:25

Take a look at the reflections library which might allow to achieve this easily:

Reflections reflections = new Reflections("my.project.prefix");
Set<Class<? extends SomeType>> subTypes = 
           reflections.getSubTypesOf(SomeType.class);

I guess you can use Object in place of SomeType as Object is the super class of all the class in java:

 Set<Class<? extends Object>> allClasses = 
     reflections.getSubTypesOf(Object.class);

How can I know the classes of a given package

3 Answers3