Why is Scala faster than Java? Scala is faster because it can utilize multi-core architecture; you get four times the speed when you can use all the four cores simultaneously. But the question remains, how can Scala be faster unless it is running on a supercomputer? The answer is: CPUs are adding capacity by addition more cores, also known as computer brains, over trying to increase CPU cycles. So, that is why they talk about dual-core or four-core CPUs in the latest computers.
The concept of concurrent functions on multiple cores is better than trying to clock existing CPUs and overheating them. But concurrency is not the only reason though because Scala runs faster on older machines too. The reason for this is Scala syntax and vocabulary is better because Scala was designed to streamline object-oriented coding. Scala code is less as compared to Java code. So, it is like reading off an index card instead of a whole book; the code runs faster because there is less to run through.
But then the question arises: don’t we lose developer efficiency because you have to reinvent the wheel relative to working with Java libraries. Well, Scala can use Java libraries; so you benefit from Java’s huge code libraries too.
But then, don’t we lose on the JVM? There are new languages written that use the JVM because it is so good. Well, Scala was written to be a replacement to Java while still using the powerful Java Virtual Machine. So, using the existing modules and the JVM with less code we end up speeding up both development as well as coding. That is why Scala is faster than Java almost across the board.
So, why then is Scala not used more often? The only reason for this is it is a new language and not a lot of programmers know it. And because languages like Coffee, Script and Lua appeared and disappeared, the adoption of Scala by people is being slowed down.
But won’t Scala down out at some point of time? Well, you can still find NASA servers running Lisp and Nuclear weapon control panels running Basic and Fortran. Java is going to be around a long time if only it is assimilated into Scala.