Scala comes in where Java fails. Scala offers a clean syntax, first-class functions, pattern matching, built-in data structures, an effective inheritance, and a built-in REPL (read-evaluate-print-loop). On top of all of these features, Scala runs on JVM and it can use existing Java libraries for all the important functions. Programmers can use all the standard Java libraries in Scala. Moreover, Scala and Java share a syntactic similarity, which makes it easier to use or import any Java resource easily.
If you are planning to learn Scala, here are some of the best books to start with Scala programming.