To quick start a new Gradle Java project, type gradle init --type java-library

$ gradle init --type java-library
:wrapper
:init
BUILD SUCCESSFUL
Total time: 4.866 secs

The following files and folders will be created automatically.

P.S Tested with Gradle 2.0

1. Java Project Structure

Both src/main/java and src/test/java folders are created. The Library*.java is a sample file, just delete it.

2. Gradle Files

1. A simple gradle.build file for Java project.

apply plugin: 'java'
repositories {
    mavenCentral()
dependencies {
    compile 'org.slf4j:slf4j-api:1.7.5'
    testCompile 'junit:junit:4.11'

2. A simple settings.build file, for multi project build. Ignore this file if you are not going to create a multi module project.

rootProject.name = 'your-project-folder'

3. Some Gradle wrapper files.

References

1. Gradle build init plugin