บทนำสู่ Groovy และ JVM

Groovy is a dynamic language for the JVM — think Java with the boilerplate stripped out. Great for scripting, web apps, and tests.

The JVM runs compiled bytecode on any OS. That is the magic behind "write once, run anywhere" — and it runs Groovy too.

Groovy compiles straight to bytecode and runs on the JVM, so it calls any Java library natively and rides the same optimizations.

Groovy's superpowers: concise syntax, optional typing, instant scripting, closures, and clean DSLs. You write less and say more.

Groovy runs on the JVM, so you need a JDK (8 or newer) installed first — grab it from Oracle or an OpenJDK build like Adoptium.

The easiest way to install Groovy is SDKMAN!, which manages JVM SDKs for you. Either way, confirm with groovy -v.

Run groovy -v to confirm your install — it prints the Groovy, JVM, and OS versions. This tiny program proves your setup works.

Here is Hello World in Groovy. No semicolons needed; for a script the main method is even optional. Notice how little it takes.

Save your code as HelloWorld.groovy, then run groovy HelloWorld.groovy from that folder. Your message prints to the console.

You met Groovy, saw how it rides the JVM and reuses Java libraries, and ran your first program. Next: Groovy's syntax and data types.