Howto load different libraries based on incoming paramters?

Question

Hello,

I am creating a java client using different libraries, they are the same base, but with different optimizations.

Is there a pattern (or something else) that I can use to load different libraries, e.g.:

java -jar myapp.jar 1 (loads with libraries from set 1 and imports correct and creates a client using this library)....

Update: I have tried OSGI and it seems like it loads jars as services. I need a way to load very similar libraries upon startup an app. The library has exactly the same package/method names, but differ in some calculation. I need to have the exact same client to get realistic results. Thanks

Answer 1

It sounds a little like the java.sql interface idea might work. Write interfaces that your clients use, then create an implementation JAR that is loaded according to a particular parameter like JDBC drivers.

Answer 2

This sounds like a good use case for OSGI. Here's some good tutorials. Each of your libraries would be a separate jar file. OSGI lets you load or unload each jar as you desire. You can swap libraries out on the fly without restarting your app in fact.

Edit:

Here is a good example app.

Answer 3

As an alternative to OSGi (which is a good way to do it) you can use Java Web Start., if your dependencies are statical one (that's to say if you won't change the library version during runtime).

If you're in that case, it's as simple as having the JNLP file generated dynamically, with the libraries version chosen according to user parameters.