From where can i get onesignal jar files
The majority of the dependencies can be resolved from the Maven, included OneSignal libraries.
The last update of Rush is from 2021 as far as I know. How can we compile with the current SDK?
You need to manually update the libraries in your Rush environment by downloading them from the ai2 sources on github.
Besides, this is not a topic for correcting faulty code. Here you can report bugs in Rush, what you show are not bugs in Rush operation.
Kindly go through this thread, you will find the solution. Set java 8 path as environment variable
I think that's happening because a newer version of java is being used?
I am using JDK 8u421
Are you using any class file that was created in a newer version of java?
No i am not using that.
java -vesion && javac -version
and show the result
What IDE are you using to write the code?
VS Code
I had the same error with VSCode and Android Studio, apparently it was due to a bad configuration that I had previously before installing Rush.
But I installed Intellij IDEA putting it in Java 8 and it worked perfectly.
I'll tell you about my experience, maybe the same thing happens.
I compiled code same code with niotron, successfully worked.
Yes, I was also racking my brain for that reason, it worked on Niotron, but not on Rush, until I did that, but your situation may be different, you could try it and see what happens.