How to use AndroidPluginLanguage to add .jar and call func?

I’m tried to link a third party android sdk(.jar and .so file) in to my project,and I found some really old solusion like 2 years ago,it’s told me to modify Android.mk file to let UBT know what file do i want to add.But it doesn’t work, because i can’t packaging a android package after i modify that file…

And then,i found a link(the following link) told me,since 4.10,the proper way to add .jar/,so is use AndroidPluginLanguage

Follow this link,i modify [project name].build.cs,and add _APL.xml file in the same director

And I do same change in Android_ETC1TargetPlatform.Build.cs and add same xml file.

Yes , now i can package again.But I don’t know my change is effect or not,because even if i add some code like"asdasdafasf" in those file,i still can package success.

Now,i want to test some func in that sdk,but i don’t know how to call func from .jar/.so file…

Finily I have 3 question

1.My change method,does it correct?

2.If is correct,how to check it effect or not?

3.If I add .jar/.so file success,how to call function in that?