CODEWITHSUNDEEP
javablackberry
Androidme
Androidme

Reputation: 3155

Adding Common class for different blackberry application

I have written a common class which I want to use in separate Blackberry applications. This class is not in a separate project but just at a common location and I have linked the path of the common class in Java Build Path. I have added same common path to both of my BB applications and they builds and installs without any problem. When I run one application, it start running but when I run the other application, it gives error message "class xxx multiply defined" error and exits.

Any idea what is going wrong here. Thanks in advance

Regards, Braj

Upvotes: 1

Views: 186

Answers (3)

Androidme
Androidme

Reputation: 3155

Thanks guys for replying. I have created a common library and put common code in that. Now I can use this library in different applications without any problem. However, when I install my applications using BB desktop Manager, the library appears as part of first application but not in second application. I assume it is because, second application realizes that the library is already been included so doesn't need to include it again.

Upvotes: 0

user784540
user784540

Reputation:

All applications in RIM OS run under one instance of Java Virtual Machine. And therefore it is allowed only one class with particular full qualified name. Adding another class with the same name will lead to failure upon running both of these classes.

There is a library thing, supported in RIM OS, but I do not recommend to use libraries in your project, unless it is very necessary.

It is because if you have several apps with the same library, but with different versions of libraries you may get the same error you reported in your question. And it is hard to manage libraries when you have many applications which use these libraries.

I recommend to copy source code of your library to the project you are working on. Copy via refactoring, to change all full qualified names of classes included in that library.

Upvotes: 1

Mister Smith
Mister Smith

Reputation: 28199

BlackBerry doesn't work as other Java platforms. In BB Java, you can't have two classes with the same full qualified name, even if they live in different projects.

You'll have to rename one of them (either change the class name or the package name) for it to work.

In fact, the only platform where I have seen this restriction is BB. It is a real pain in the ass since you can't reuse a jar library in different projects without renaming it.

UPDATE:
This is the official article on the topic:
http://supportforums.blackberry.com/t5/Java-Development/Application-throws-quot-multiply-defined-quot-error-at-start-up/ta-p/501498

Upvotes: 2

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