DevNexus 2018 – Gradle – the basics and beyond

Title: Gradle – the Basics and Beyond
Speakers: Ken Kousen

For more blog posts, see the DevNexus 2018 live blogging table of contents


  • requires Java 7+
  • Gradle 4.2.1+ supports Java 9
  • Gradle releases frequently but is very backward compatible
  • Just unzip and add to path
  • The complete distribute includes the samples. The sample sources are also available online.


  • Gradle is now much faster than Maven
  • is the enterprise version which is built on top of open source
  • Gradle is mostly implemented in Java. Groovy is for the DSL.
  • Uses Ant behind the scenes as well
  • Groovy comes with Gradle. Don’t need to install Groovy separately
  • gretty is jetty for gradle; also contains tomcat



  • Kotlin
    • Creating a Kotlin DSL for simple build files.
    • Kotlin is not replacing Groovy
    • Not yet at 1.0.0
    • Goal is better IDE integration
  • Generator
    • Looking at being able to generate projects on web project like Spring Boot has


  • Recommend using gradlew. Checking in the file guarantees users are on version of gradle that you intended
  • Has effect of creating many gradle installs on your machine. Not that big.

Creating a project

  • Can generate new project or port basic pom files.
  • Use porting as a guide and then hand edit
  • Generate new project in current directory (make empty directory by hand first)
    • mkdir proj
    • cd proj
    • gradle init –type java-application (or java-library)
  • Files/directories in project
    • gradlew/gradlew.bat – wrapper script
    • gradle/wrapper – jar and properties
    • settings.gradle – lists multi project builds
    • – key/value pairs used by build
  • In home directory’x .gradle
  • wrapper/distx – the binarry/installs.


  • Improves performance
  • Cache a lot of the JVM startup
  • For a few hours, same daemon used if using same version of gradle on every project.
  • Tip: turn off daemon on CI servers so every build is a clean build

Gradle file

  • repositories
    • can use jcenter or maven central.
    • or can specify a different one for any Maven or Ivy repo; like internal corporate one
    • can list multiple repos and searches in order
  • dependencies
    • ‘group:name:version’ – same concept as Maven GAV. Or can split into three sections. Ken likes the former better; either fine.
    • can write compile (‘g:n:v’) to specify fully. Groovy parens are optional except when they are not. The DSL can interpret without parens and easier to read.
    • New Java plugin has api/implementation to use as scope instead of compile.
    • compile files – lets you add files not in the classpath
    • compile fileTree – lets you add a directory not in the classpath
  • plugins
    • if registered on, can list id and version numbers.
    • built in plugins (ex: java) don’t get a version number


  • gradle build -t – rebuilds and then sits idle until you change code. Like a rebuild loop
  • gradle build –dry-run – shows what would run (can use -m instead of –dry-run)
  • gradle -b… – use different build file name
  • gradle –stsatus – shows processes

Build scan

  • Starting Gradle 4.3, will prompt you if you haven’t accepted the license agreement and try to use.
  • It’s hosted at Gradle so sends some info out.
  • Gradle Enterprise does build scans in house

My take

Good structured intro/review. Happy that Ken changed the background to white when we were reading code. He also made the code sufficiently large. I didn’t even need my glasses. Go Ken! The only time I needed my classes was when he showed the manual which uses dark gray on a light gray background for the comments. I knew more of the basics than I realized. But good to have it gel better in my head! And I definitely learned things. Rushed at the end though and that was where most of the new stuff is. Glad I’m a New Yorker and can handle talking fast. Can’t type that fast though so stopped taking notes.

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