title: gradle classes are not generated
body: <p>I am trying to convert my project to gradle and unable to get the class files generated under build folder. Here is the build.gradle file:</p>
  
  <pre><code>import org.gradle.internal.os.OperatingSystem;
  apply plugin: 'java'
  
  sourceCompatibility = 1.8
  targetCompatibility = 1.8
  
  sourceSets {
      main {
          java {                  
              srcDirs = ["abc/def/"]
              include('include/Constants.java')                                   
              }
          }
  }
  
  task initial(type: Exec) {
      doFirst {
      println 'Started compiling constants'
    }
    if(OperatingSystem.current().isWindows()) { 
      println 'Compiling on windows'
      //Run some bash script here
    }
    else {
      print 'Compiling on unix'
      //Run some shell script here
    }
    doLast {
      println 'Finish compiling constants'
    }
  }
  
  jar {
      baseName = 'output' 
  }
  
  dependencies {
      compile files('../lib/log4j/log4j.jar')     
      compile files('../lib/findbugs/findbugs.jar')   
      compile files('../lib/guava/guava-19.0.jar')    
  }
  </code></pre>
  
  <p>When i do gradle build, it says successfull, but see no classes generated under build folder.
  Any help?</p>