Call scala from java - performance?

Question

I have parser written in Scala due to implementation simplicity. I need to call it from my java application. I know I need to include scala library in the classpath, etc. But what about performance? Could it be any strong performance decreases comparing the pure java parser calls?

Answer 1

Calling Scala from Java isn't going to incur any overhead: it's all just bytecode when it executes. It's not as if you were having to travel through some kind of bridge between Java and Scala, as you might if you were calling from Java into, I don't know, Python.

Whether the Scala implementation of this particular algorithm is going to run faster or slower will depend on the nature of the algorithm and the way you'd implement it. Given that you're not going to implement it the same way in the two languages, it's very hard to predict.

Answer 2

In theory there should not be any impact, as Scala uses the same JVM and bytecode as Java and all performance test I've seen give roughly the same speed to both languages.

That is, it should be the same (performance wise) to calling a Java library, or so similar that the difference shouldn't matter.