Java library yeoman generator

About

Generates java library project (or multi-module library), hosted on github with maven central publication. Ideal for new OSS project quick start.

Features:

• Single and multi-module projects generation
• MIT license (hardcoded)
• Gradle build (with support of optional and provided dependencies)
• Maven central compatible artifacts (jar, sources, javadocs)
• Ready for spock tests (documentation)
• CI: github actions (linux), appveyor (windows)
• Coverage with jacoco, merged from both win and linux builds in codecov.io
• Target jdk compatibility check with animal sniffer (you may use newer jdk to build, and keep compatibility with older jdk)
• Code quality checks (checkstyle, pmd, findbugs)
• Release process (like maven release)

Requires jdk8 or above (due to checkstyle requirement). But actual library could target any java level (jdk8 is only required for build).

Known issue

Gradle 2.13+ has a bug with console input. As a result, during release version confirm questions are not visible.

Issue is not blocking and only affects release process: simply hit enter for questions (and be sure version in properties file is correct).

Thanks to

• Vladislav Bauer (android-arsenal author) for checkstyle config and gitignore.io hint
• Juan Roperto for pmd config

Example projects

Single module

• dropwizard-guicey
• guice-validator
• guice-persist-orient
• dropwizard-orient-server
• generics-resolver

Multi-module

• guice-ext-annotations - with published BOM
• yaml-config-updater - without BOM

Setup

Install yeoman:

$ npm install -g yo

Install generator:

$ npm install -g generator-lib-java

Github setup

You will need github user. Create it if you don't have already.

Maven central setup

For maven central publication you must first register in sonatype and approve your group. Read this a bit outdated article for getting started.

For certificate generation see java-lib plugin docs Note that signing configuration required only for release (otherwise its ignored)

After all you'll need to put the following properties into ~/.gradle/gradle.properties

sonatypeUser =
sonatypePassword =

signing.keyId = 78065050
signing.password =
signing.secretKeyRingFile = /path/to/certs.gpg

Generator will check and warn you if something is not configured.

Publishing library to local repository only

If library is assumed to be used as internal library with local (corporate) maven repo, manual modifications required.

Remove io.github.gradle-nexus.publish-plugin.

Remove ru.vyarus.github-info (I assume your source would not be in github). And remove related github configuration block.

Remove signing plugin if you don't need to sign artifacts for your repository.

Configure repository:

publishing {
    repositories {
        maven {
            url project.version.contains("SNAPSHOT")
                    ? "https://my-private-nexus.com/nexus/content/repositories/my-snapshots"
                    : "https://my-private-nexus.com/nexus/content/repositories/my-releases"
            credentials {
                username = project.findProperty('myRepoUser')
                password = project.findProperty('myRepoPass')
            }
        }
    }
}

Change releasing task:

afterReleaseBuild {
    dependsOn = [publish]

Now simple publish task deploys snapshot version and release task would perform complete release (with version change and tagging git).

To use published library declare custom repository in target project:

repositories {
    // usually root repo combining releases and snapshots
    maven { url 'https://my-private-nexus.com/nexus/content/groups/my/' }
}

Usage

General convention: project name == github project name == bintray package page

Run generator:

$ yo lib-java

Generator creates project in current folder if project name (question) is the same as current directory, and will create subdirectory otherwise.

Generator calls github to validate user correctness and suggest your name and email. If there is a problem with it use offline mode:

$ yo lib-java --offline

Project setup ready, start coding!

Build upgrade

If generator started in folder with already generated project - it will work in update mode. This will allow you to easily update existing build with new generator version.

Update mode skips some files to reduce update to only meaningful files (e.g. no need to update CHANGELOG.md, gradle.properties etc). Update will use previous answers by default.

Start update without local changes and after generation look git changes and correct (usually only main build.gradle requires modifications after update).

Global storage

Most likely, some answers will be the same for all your libraries, that's why they are stored in global config and you will see more precise defaults on next generation.

Global config stored in ~/.config/configstore/generator-lib-java.json

External services

Create github repo matching your library name and push project there (github will guide you).

In github project settings go to Webhooks & services and add travis-ci service.

Enable repository on appveyor

And after next commit windows and linux builds will be performed automatically and combined coverage report will be available on codecov (badges for all services are already generated in readme).

Maven central badge is generated in readme.

Snapshots

JitPack is ideal for snapshots: it builds github project and serves dependency for you. Special section in project readme is generated to show how to use it for snapshots. JitPack doesn't require any configuration to support your library.

Gitter

Gitter is a chat room for your repository. Most likely, with it you will get much more feedback (something people will never post as issue or write by email).

Gitter badge is not generated automatically, because it's not required as other services and it's too easy to add at any time. Look it and decide if you need it.

Documentation

You can use gradle-mkdocs-plugin for writing versioned project documentation (published on github pages).

Project usage

$ gradlew check

Runs code quality plugins and tests. If quality checks were activated (asked during generation) do check before pushing to avoid build failures on travis. Moreover, it's easy to always keep everything clean instead of doing it before release.

$ gradlew dependencyUpdates

Checks if your project dependencies are actual and prints versions analysis report to console.

$ gradlew dependencies

Prints dependencies tree into console

$ gradlew openDependencyReport

Generates dependencies html report and launch it in default browser. To analyze conflicts, click on dependency name to activate dependencyInsight popup.

$ gradlew install

Installs library to local maven repository. Useful for referencing by other projects (for testing without releasing library).

$ gradlew release

Releases library. Read release process section below before performing first release.

Project details

Used gradle plugins:

• java
• groovy to support spock tests
• maven-publish to generate pom and publish to maven repository
• project-report to generate dependency tree html report
• jacoco to build coverage report for coveralls
• pmd to check code quality with PMD tool
• checkstyle to check code style rules with checkstyle
• spotbugs to find potential bugs with spotbugs
• o.github.gradle-nexus.publish-plugin to simplify maven central publication
• com.github.ben-manes.versions to check dependencies versions updates
• net.researchgate.release for release (see article for additional plugin details)
• ru.vyarus.pom for simpler pom generation
• ru.vyarus.java-lib to prepare java artifacts setup
• ru.vyarus.github-info to fill in github specific data
• ru.vyarus.quality to configure quality plugins and provide advanced reporting

Optional dependencies

Optional and provided dependencies support provided by ru.vyarus.pom plugin.

Example usage:

provided 'com.github.spotbugs:spotbugs-annotations:3.1.2'

or

optional 'com.github.spotbugs:spotbugs-annotations:3.1.2'

In the generated pom these dependencies will be defined as provided or optional, but for gradle build it's the same as declaring them in implementation scope.

jsr305 provided dependency is defined by default in generated project (useful to guide firebug).

Scala note: The Scala compiler, unlike the Java compiler, requires that annotations used by a library be available when compiling against that library. If your library users will compile with Scala, they must declare a dependency on JSR-305 jar.

Quality tools

Quality tools are configured by ru.vyarus.quality plugin.

Read more about quality tools specifics and how to suppress warnings:

• checkstyle
• pmd
• spotbugs

By default, quality checks fail build if any violation found. In order to simply report violations do:

quality {
    strict = false
}

Release process

Before first release

When releasing first time it's better to do

$ gradlew install

And validate generated pom file and jars (in local maven repository ~/.m2/repository/..).

General release process

Update CHANGELOG.md.

Push all changes before release and wait for travis to check build (wait for green badge).

Perform release:

$ gradlew release

Release will check that current copy is actual: no uncommitted/unversioned/unpushed changes, nothing newer is in remote repository. You can start releasing either from snapshot version (1.0.0-SNAPSHOT) or from normal one (1.0.0).

During release, plugin will create tag (new github release appear) and update version in gradle.properties.

You may want to create github release: release will only create tag. To create release go to github releases, click on tag and press 'edit'. I usually use text from changelog as release message, but you may expand it with other release specific notes.

Support

Gitter chat room