How to create Java gradle project

Question

How to create Java Gradle project from command line?

It should create standard maven folder layout like on the picture below.

Answer 1

Here is what it worked for me.. I wanted to create a hello world java application with gradle with the following requirements.

1. The application has external jar dependencies
2. Create a runnable fat jar with all dependent classes copied to the jar
3. Create a runnable jar with all dependent libraries copied to a directory "dependencies" and add the classpath in the manifest.

Here is the solution :

• Install the latest gradle ( check gradle --version . I used gradle 6.6.1)
• Create a folder and open a terminal
• Execute gradle init --type java-application
• Add the required data in the command line
• Import the project into an IDE (IntelliJ or Eclipse)
• Edit the build.gradle file with the following tasks.
  

Runnable fat Jar

task fatJar(type: Jar) {
 clean
 println("Creating fat jar")
 manifest {
    attributes 'Main-Class': 'com.abc.gradle.hello.App'
 }
 archiveName "${runnableJar}"
 from {
    configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
    configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) }
 } with jar
 println("Fat jar is created")
}

Copy Dependencies

task copyDepends(type: Copy) {
   from configurations.default
   into "${dependsDir}"
}

Create jar with classpath dependecies in manifest

task createJar(type: Jar) {
   println("Cleaning...")
   clean
   manifest {
    attributes('Main-Class': 'com.abc.gradle.hello.App',
            'Class-Path': configurations.default.collect { 'dependencies/' + 
             it.getName() }.join(' ')
    )
}
  from {
      configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
  } with jar
  println "${outputJar} created"
}

Here is the complete build.gradle

plugins {
    id 'java'
   id 'application'
}
repositories {
    mavenCentral()
}
dependencies {
  implementation 'org.slf4j:slf4j-api:1.7.30'
  implementation 'ch.qos.logback:logback-classic:1.2.3'
  implementation 'ch.qos.logback:logback-core:1.2.3'
  testImplementation 'junit:junit:4.13'
}
def outputJar = "${buildDir}/libs/${rootProject.name}.jar"
def dependsDir = "${buildDir}/libs/dependencies/"
def runnableJar = "${rootProject.name}_fat.jar";

//Create runnable fat jar
task fatJar(type: Jar) {
   clean
   println("Creating fat jar")
   manifest {
    attributes 'Main-Class': 'com.abc.gradle.hello.App'
  }
  archiveName "${runnableJar}"
  from {
    configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
    configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) }
  } with jar
  println("Fat jar is created")
}

//Copy dependent libraries to directory.
task copyDepends(type: Copy) {
 from configurations.default
 into "${dependsDir}"
}

//Create runnable jar with dependencies
task createJar(type: Jar) {
 println("Cleaning...")
 clean
 manifest {
    attributes('Main-Class': 'com.abc.gradle.hello.App',
            'Class-Path': configurations.default.collect { 'dependencies/' + 
            it.getName() }.join(' ')
    )
 }
 from {
     configurations.compile.collect { it.isDirectory() ? it : zipTree(it) }
 } with jar
  println "${outputJar} created"
}

Gradle build commands
Create fat jar : gradle fatJar
Copy dependencies : gradle copyDepends
Create runnable jar with dependencies : gradle createJar

More details can be read here : https://jafarmlp.medium.com/a-simple-java-project-with-gradle-2c323ae0e43d

Answer 2

To create a Java project: create a new project directory, jump into it and execute

gradle init --type java-library

Source folders and a Gradle build file (including a wrapper) will be build.