…be used as a direct replacement for it — in fact, it’s compiled to run on the Java Virtual Machine. It’s a complex language to learn, but well worth it in the end: Scala was ranked in the top-paying tech in Stack Overflow’s 2017 and 2018 survey.
Maybe for people who don’t already know Java. Read Scala for the Impatient by Cay Horstmann. You might find it a breeze, until you hit a wall with the chapter on lexical parsers.