plugins {
  id "org.springframework.boot" version "1.5.10.RELEASE"
}

dependencies {
...
}

jar.dependsOn compileGwt

jar {
  into("static") {
    from compileGwt.buildDir
  }
}

apply from: "$rootDir/gradle/gwt.gradle"

dependencies {
...
}

compileGwt {
  classpath {
    [
        sourceSets.main.java.srcDirs,           // Java source
        sourceSets.main.output.resourcesDir,    // Generated resources
        sourceSets.main.output.classesDir,      // Generated classes
        sourceSets.main.compileClasspath,       // Deps
    ]
  }
}

task compileGwt(dependsOn: classes, type: JavaExec) {
...
}

def generatedDir = new File("$projectDir", "src/generated")

apply plugin: 'java'

sourceSets {
  generated {
    java.srcDir "src/generated/java"
  }
  main.java.srcDirs = ['src/main/java', "src/generated/java"]
  main.resources.srcDir "src/main/resources"
  test.java.srcDir "src/test/java"
  test.resources.srcDir "src/test/resources"
}

// deletes generated classes before new compilation
task deleteGenerated(type: Delete) {
  generatedDir.deleteDir()
}

compileGeneratedJava {
  dependsOn('deleteGenerated')
}

compileJava {
  sourceCompatibility = "1.8"
  targetCompatibility = "1.8"
  options.encoding = 'UTF-8'
  options.compilerArgs = ['-Xlint:unchecked'] // Just a smoke test that using this option does not lead to any
  options.annotationProcessorGeneratedSourcesDirectory = new File("$generatedDir", "java")
  dependsOn(processResources, compileGeneratedJava)
  source += sourceSets.generated.java
  source += sourceSets.generated.output
}

test {
  systemProperties = System.properties
}