Possible to use two java classes with same name and same package?

Is it possible to import and use two different classes with the same name and package in java?

For example, let's say I have two classes named "com.foo.Bar" that are slightly different. I'd like to be able to use both, but I have a restriction (because of stupid reflective crap) that forces me to keep the na开发者_如何学编程mes and packages the same.

Is there some feature of java that would allow me to import and isolate each of these classes?

To elaborate, I changed my avro schemas in ways that they shouldn't have ever been changed (oops!) and now I'd like to go back and change the old avro files that can't be read with my new schema into files that can be read by my new schema. Avro seems to force you to use a specific class and package name to load the files.

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Yes there is. You would need to implement your own Classloader and play some games to be able to access both during runtime.

I'm sure this is possible, because I ran into a very hard to debug issue where someone had a weird Classloader in their product that was messing up loading libraries and providing 2 different versions of the same file from 2 different versions of the library.

However, this sounds like an INCREDIBLY bad idea. I'd go back and find a different way of fixing your issue. This will only bring you heartache in the long run. Heck, it probably already is, as you investigate class loaders.

EDIT: To be specific, you cannot "import" both. But you can access both at runtime.

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No, java packages are used precisely to avoid that problem.

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Yes it is. It does require you to make your own ClassLoader, though

I had made a demo of that on github to!

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If you really most definitely must do something like this, you can achieve it by using different classloaders and possibly reflection.

This is not the way Java works and it's not allowed on purpose - you shouldn't be doing stupid things which will screw up things for you.

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There are no namespaces in Java, only in C#, so I assume you mean packages. There can only be one fully qualified name per project.

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Technically it can be done using some low-level trickery such as rewriting the byte-level code. As far as I know the different java crypter/encrypters work like that - they have a lot of classes called A.class B.class C.class etc.

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It sounds to me like you need to define your method signatures in an interface called com.foo.Bar. Then provide two different concrete implementations of the interface (say, com.foo.DefaultBar, and com.foo.SpecialBar). This way, you can program against the interface type, and switch between the two different implementations as required.

Can you elaborate on what you mean by "reflective crap"? That may provide insight into your exact issue.

Don't mess with the class loader or any other low level trickery. The best way to solve such issues it to have a clear design in the first place that anyone can understand.

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As already mentioned writing your own Classloader or additionally use a OSGi framework like Equinox which does the classloading for you