Modern java is a fairly good language. If you don't like it, can always opt into scala, kotlin, or clojure. I don't understand what you mean by Java not working on multiple platforms. If you like c#/.net that's fine but why try to put down Java which has been cross platform for a long time?
Cross platform is less and less important nowadays. When was the last time your phone ran a Java application natively? As in you had a legit JVM on your phone?
Everything is cross-compiled or cross-translated to something else. I write C# for Unity and it translates it to something that'll run on iOS, which definitely doesn't have the CLR natively in it.
