Import Java Project in Android application?

Question

Can I use a Java Project in an Android Project even if some classes from the java project are not recognized in a normal android project? For example javax.xml package?

There are 2 possibilities as I see it:

1. Either create a jar with that java project and import it in android
2. Or reference the project in android(as i understood it's possible).

But in either way, will those classes that are found in java but not in android be ok in my Android Application? Will this work? Thank you.

I made the JavaProject, and then imported it in my Android Project as a reference. I get an error i did not expect, it does not recognize my .classes from my Java Project.

Answer 1

If you are using Eclipse (with the ADT plugin) you can reference the Java project in the build path of your Android project. This will package those classes in your .apk output and allow you to use them in your app.

As you pointed out in your comments; referencing a Java project as an Android library will not work in your case, since the presence of the javax.* packages will result in compile time errors in Eclipse. In this case, you will need to opt for option 1 and build a Jar file from your Java project and include it as explained here. This way, the class files requiring javax.* should not produce any compile/runtime errors unless you try to use them. Either way, using the Java build path will not work as you expect - the class files are not bundled this way.

The Android platform provides some of javax.xml, but not the whole package (read this document for more detail on this). Often the easiest solution is to write an Android equivalent of your affected Java code that does not require the missing dependencies, and bridge the 2 implementations so the correct one is used for each project.