title: gradle javadoc fail on UTF-8 chars, only on windows
body: <p>So i have a gradle based java project, with tons of hungarian docs string, witch mean a lot of non ASCII character. </p>
  
  <p>It's perfectly fine since javac consume utf-8 characters in source code,and javadoc also should according to my knowledge.</p>
  
  <p>In the build gradle has a task which create the java doc jar</p>
  
  <pre><code>task javadocJar(type: Jar, dependsOn: javadoc) {
      classifier = 'javadoc'
      from javadoc.destinationDir
  }
  
  artifacts {
      archives sourcesJar
      archives javadocJar
  }
  </code></pre>
  
  <p>When i run <code>gradle build</code>, it's fail with the following error:</p>
  
  <blockquote>
    <p>:compileJava
    C:\Home\Projects\InventoryCore\src\main\java\hu\rfit\inventory\models\entities\ItemState.java:11:
    error: unmappable character for encoding Cp1252  * ├?ru / term├⌐k
    ├íllapot.
        ^ :processResources UP-TO-DATE :classes :jar :javadoc C:\Home\Projects\InventoryCore\src\main\java\hu\rfit\inventory\models\entities\ItemState.java:11:
    error: unmappable character for encoding Cp1252  * ├?ru / term├⌐k
    ├íllapot.
        ^ 1 error :javadoc FAILED</p>
    
    <p>FAILURE: Build failed with an exception.
    What went wrong:
    Execution failed for task ':javadoc'.
    Javadoc generation failed. Generated Javadoc options file (useful for troubleshooting): 'C:\Home\Projects\InventoryCore\build\tmp\javadoc\javadoc.options'</p>
  </blockquote>
  
  <p>The best part is it's running perfectly in build pipeline, and on my other os (ubuntu 16.04 lts) it's fail only on windows.</p>
  
  <p>I have already tried a fresh clone of the git repo, updated the the java jdk to the newest(oracle jdk 1.8.0_131 before was a _73 and _111 tried both).
  All the files in the project are utf-8 encoded, and also tried put javadoc setting into my <code>build.gradle</code> file, </p>
  
  <pre><code>javadoc {
      options.charSet = 'UTF-8'
  }
  </code></pre>