[JAVA] Scala runs on the JVM

JRE and JDK

JRE is an execution environment in (Java Runtime Environment) JDK is a development tool (Java Development kit) That is. JDK is used in scala.

JRE is OK if you just want to run the compiled program If you need to compile a program, you need a JDK Since the JDK also includes the JRE, there is no problem if you install the JDK in scala.

Command type

Java command is a command to start a Java application Javac commands are commands for compiling java source code

Benefits of scala running on the JVM

-It is a portal execution program that is not affected by differences in OS.

-You can call existing java modules including the java standard library. You can benefit from the accumulated knowledge of java

-Runtime performance is reasonably fast.

Disadvantages of running on the JVM

Of course there are disadvantages if there are advantages -This is not a problem for applications such as server applications that are always running, but for applications that are executed each time from the command line, it may become a bottleneck that it takes a certain amount of time to start the JVM. -Compared to languages with a small run-time memory footprint such as Go, even small applications use a large amount of memory. There are the above disadvantages.

Scala events

In recent years, the number of companies that mainly use service operating companies has been increasing. The largest Scala conference in Asia is held every year in Tokyo. Its name is "Scala Matsuri" I would like to participate in the next event.

Development environment

There are text editors and IDEs.

Reference book

Introduction to Practical scala

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