Getting Started with Groovy

Groovy is a dynamic language for the Java platform. It runs on the JVM, uses Java’s libraries directly, and accepts almost all Java syntax — but adds shortcuts that make everyday code dramatically shorter. That’s why it’s everywhere scripts are needed in the Java world: Gradle build files, Jenkins pipelines, Spock tests, and Boomi Data Process scripts (see the Boomi Groovy guides on the blog).

If you know some Java, you already know a lot of Groovy. If you don’t, Groovy is a friendly first language: less ceremony, instant results.

Install Groovy

Groovy needs a JDK (see Getting started with Java). Then the easiest route is SDKMAN (macOS, Linux, Windows via WSL or Git Bash):

curl -s "https://get.sdkman.io" | bash
sdk install groovy
groovy --version

On Windows without SDKMAN, download the binary zip from groovy-lang.org, unzip it and add its bin folder to your PATH.

Tip: If you write scripts for a specific platform — Boomi, Jenkins, Gradle — check which Groovy version it uses and install the same major version locally. Newer versions moved some classes between packages.

Three ways to run Groovy

1. groovyConsole — a playground window

groovyConsole

Type code in the top half, press Ctrl+R (Cmd+R on Mac), see the output below. Perfect for experiments.

2. groovysh — the interactive shell

groovysh
groovy:000> 24 * 8.5
===> 204.0
groovy:000> 'po-4471'.toUpperCase()
===> PO-4471

3. Scripts

Groovy doesn’t need a class or a main method. A file with statements is a program:

// hello.groovy — your first Groovy script.  Run:  groovy hello.groovy
println 'Hello, Groovy!'

def name = args ? args[0] : 'Groovy learner'
println "Welcome, $name!"

// Groovy runs Java too: any Java code is (almost always) valid Groovy
System.out.println("Java style works as well");
println "Java version: ${System.getProperty('java.version').split(/\./)[0]}+"

Run it:

groovy hello.groovy
groovy hello.groovy Chirag

Hello, Groovy!
Welcome, Groovy learner!
Java style works as well
Java version: 21+

Java vs Groovy at a glance

The same task in both languages — print the names of active customers, uppercased:

// Java
List<String> result = new ArrayList<>();
for (Customer c : customers) {
    if (c.isActive()) {
        result.add(c.getName().toUpperCase());
    }
}
System.out.println(result);

// Groovy
println customers.findAll { it.active }*.name*.toUpperCase()

You’ll understand every symbol in that one-liner by the end of the closures and collection methods lessons.

Try it yourself

Write a script that prints the current date and time, then counts from 1 to 5 on one line.

println "Now: ${java.time.LocalDateTime.now()}"
println((1..5).join(' '))

Key takeaways

• Groovy runs on the JVM, uses Java libraries and accepts most Java code.
• Install it with SDKMAN (or the zip) on top of a JDK.
• Use groovyConsole or groovysh to experiment; run files with groovy file.groovy.
• Scripts need no class or main method.