Welcome to the RingCentral Community

Here is a working project https://github.com/tylerlong/ringcentral-jar-demo

You need to download and add the following jars to your project:

1. // https://bintray.com/tylerlong/maven/ringcentral/1.6.1#files
2. // https://bintray.com/bintray/jcenter/org.jetbrains.kotlin%3Akotlin-stdlib/1.3.50#files
3. // https://bintray.com/bintray/jcenter/com.google.code.gson%3Agson/2.8.6#files
4. // https://bintray.com/bintray/jcenter/com.squareup.okhttp3%3Aokhttp/3.14.2#files
5. // https://bintray.com/bintray/jcenter/com.squareup.okio%3Aokio/1.17.2#files

I don't think we need to hack the JVM. But we do need the kotlin-stdlib jar file. It's just a jar file like other jar files. So I don't think it would be an issue for you.

We added the JARs manually, but it appears that the RingCentral JAR is dependent on the Kotlin JVM and we are unable to inject Kotlin into our runtime. We are deploying into an application that manages the JVM internally and does not allow for us to modify the JVM components.

Am I understanding how Kotlin is utilized in your SDK correctly? Do you have a version that is not Kotlin dependent?

You can download jar file here https://bintray.com/tylerlong/maven/ringcentral/1.6.1#files/com/ringcentral/ringcentral

You need to download dependent libraries yourself: https://github.com/ringcentral/ringcentral-java/blob/master/build.gradle#L21-L22

We don't provide a standalone jar file which includes all dependencies. Because dependent libraries are not maintained by us, it is not a good idea to include other jar files inside ours.