build.gradle

repositories {
 mavenCentral()
}

apply plugin:'java'

configurations {
  metamodel
  validator
  processor
}

dependencies {
  compile 'org.hibernate:hibernate-core:4.3.5.Final'

  metamodel 'org.hibernate:hibernate-jpamodelgen:4.3.5.Final'
}



ext.generatedDir = project.file("$buildDir/source-generated")
ext.jpaDir = project.file('src/main/jpa')

sourceSets {
  main {
    java {
      srcDir jpaDir
    }
  }
}

// Step 1
task process1(type: JavaCompile) {
  classpath = sourceSets.main.compileClasspath + configurations.metamodel
  source sourceSets.main.java

  destinationDir = generatedDir
  options.compilerArgs = [
    '-proc:only'
  ]
}

// Step 2
task process2(type: JavaCompile) {
  classpath = sourceSets.main.compileClasspath
  source sourceSets.main.java, generatedDir

  destinationDir = file("$buildDir/classes")

  dependsOn process1
}

compileJava {
  classpath = sourceSets.main.compileClasspath
  source = jpaDir

  destinationDir = file("$buildDir/classes-jpa")

  dependsOn process2
}