Gradle 2.Write once, build everywhere.

Sergey Morenets, morenets@mail.ruJune, 6 2015

About author• Works in IT since 2000• 11 year of Java SE/EE experience• Regular speaker at Java conferences• Author of “Development of Java applications” and

“Main errors in Java programming ”books• Founder of http://it-simulator.com• 3 years of Gradle usage

Agenda

Agenda

Agenda

Apache Ant• Offers extreme flexibility• Imposes no convention or project standards• Maintenance headache• Support Ruby, Groovy, JavaScript, Judoscript,

Jython scripting

Apache Ivy• Agile dependency manager• Transitive dependencies• Ant & Maven integration• Enhanced support of repositories

Apache Maven

• Support for dependency management• Standard project layout• Archetypes• Hard customization• Declarative approach• Plugin execution framework

Build systems

Apache Maven

Ant plugin

Groovy plugin

Echo plugin

Gradle

Issue #1. XML

• Large and complex files are hard to understand• Hierarchical structure limits the expressivenessof the format• Good format for the data and complex for the

flow

Hans Dockter• Founder of Gradle and Gradleware• 13 years of experience as a software developer,

team leader, architect, trainer, and mentor• Previously worked at Jboss and founded Jboss-IDE• Holds a Diploma in Physics with a minor in

Computer Science• Admirer of domain-driven-design

Slogan• Make the impossible possible• Make the possible easy• Make the easy elegant

Solution #1. Groovy

• An agile and dynamic language for the Java Virtual Machine

• Makes modern programming features available to Java developers with almost-zero learning curve

• Provides the ability to statically type check and statically compile your code for robustness and performance

• Share base syntax, type system, packages hierarchy with Java

• Every Gradle build file is Groovy script

Gradle

Gradle• Development started in Apr 2008• Current version 2.4 released in May 2015• Default build tool for Android OS

Gradle overview

• A flexible general purpose build tool• Programming tool• Declarative builds and build-by-convention• Multi-project support• Powerful dependency management

Development

Version Release dateMaven 1.0 2004

Maven 2.0 2005

Maven 3.0 2010

Maven 3.1 2013

Maven 3.3 2015

Development

Version Release dateGradle 0.7 2009

Gradle 1.0 2012

Gradle 1.5 2013

Gradle 2.0 2014

Gradle 2.4 2015

Build structure

Hello world

$ gradle helloWorld

build.gradle

Maven pom

Sample project

Sample project

Custom task

• Writes audit information at the end of the build• Audit information includes project name and build

timestamp• Audit files are located in the separate folder

Custom task

Custom task

Cache everything

• Remote metadata and artifacts• Transitive dependency resolution• Build execution plan• Plugin inputs and outputs• Test results

Daemon

• Improves startup and execution time of Gradle• Initial Gradle command forks daemon process• Subsequent Gradle commands reuse the build

daemon• If daemon is currently busy then new daemon

process is started on-demand• Useful for small tasks execution• Expires after 3 hours of idle time

gradle.properties

• org.gradle.daemon=true• org.gradle.configureondemand=true• org.gradle.parallel=true• org.gradle.java.home=C:\\Program Files\\Java\\

jdk1.8.0_45\\• org.gradle.jvmargs=-Xmx100m

Test execution

# of threads

H2 – time(sec) MySQL – time(sec)

1 24,4 27,5

2 31,1 36,9

4 46,2 51,1

8 71,1 80,5

Plugin• Reusable pieces of build logic• Can be used in different projects/builds

Plugin• Add tasks to the project• Pre-configure added tasks with useful defaults• Add dependency configurations to the project • Add new properties and methods to existing type

via extensions

Plugin import

Plugin portal

Custom plugin

gradle helloWorld

Maven

Gradle

Integrates with everything

Gradle and Maven

Properties

Properties

Comparison

• Maven 3.3.3• Gradle 2.4• JDK 1.8.0.45• Intel Core i7, 4 cores, 16 GB• Optimized and default modes

Comparison

Operation Gradle (opt)

Gradle (daemon)

Gradle(no daemon)

Maven

Maven (parall)

Build(sec) 8,03 10,73 13,68 12,40 13,02

Inc build(sec)

1,92 2,16 4,74 4,62 4,64

Clean(sec) 1,03 1,20 2,77 1,71 1,70

Gradle

Optimized Not optimized

Maven

Optimized Not optimized

Maven converter

• maven2Gradle is obsolete now• Build init plugin converts:

o POM settingso Dependencieso Propertieso Java compiler settingso Single- and multi-project settingso Packaging of sources and tests

Repositories

Maven Scope

Maven Scope

Scopes:• compile• provided• runtime• test• system• import

Dependencies

Scope flexibility

Version management

Profiles

• build.gradle• dev-profile.gradle• test-profile.gradle

• $ gradle –Pprofile=dev build

Skip tasks

• $ gradle -PskipTests

Caching

• Gradle caches all compiles scripts by default• Compiled scripts are put into .gradle folder• Gradle uses compiled version if the script hasn’t

changed• --recompile-scripts option discards cache

Wrapper

• Preferred way of starting a Gradle build• Gradle will be automatically downloaded via

wrapper• Includes shell script• Useful for CI tasks

Practical tasks

• Multiple projects• Liquibase• Deployment

Multiple projects• Huge project• Multiple sub-projects/pom.xml files• Complicated maintenance

Liquibase• Plugins for 2 and 3 versions• Lightweight front-end for Liquibase command-line• Gradle task for each Liquibase command

Deployment

• Separate plugins for Jetty/Tomcat• General plugin for multiple containers

Cargo plugin

Cargo plugin

Pros• Native Java/Scala/Groovy support• Ant/Maven/Ivy integration• Full IDE support• Flexible DSL• Multiple third-party plugins(70+)• Declarative & imperative approaches• Rapid development• Performance

Cons• Compilation & run-time issues• Larger learning curve• Less community & industry support

Future

Practice

• https://github.com/hibernate/hibernate-orm• https://github.com/SpringSource/spring-

framework• https://github.com/gradle/gradle

Q&A

• Sergey Morenets, morenets@mail.ru