title: ThreeTen-Backport error on Android - ZoneRulesException: No time-zone data files registered
body: <p>I'm using ThreeTen-Backport library for my Android project (because java.time is not yet implemented in android development).  </p>
  
  <p>When I write <code>LocalDate today=LocalDate.now();</code> or <code>LocalTime time=LocalTime.now();</code> I get the following exception:</p>
  
  <pre><code>Caused by: org.threeten.bp.zone.ZoneRulesException: 
    No time-zone data files registered   
        at org.threeten.bp.zone.ZoneRulesProvider.getProvider(ZoneRulesProvider.java:176)
        at org.threeten.bp.zone.ZoneRulesProvider.getRules(ZoneRulesProvider.java:133)
        at org.threeten.bp.ZoneRegion.ofId(ZoneRegion.java:143)
        at org.threeten.bp.ZoneId.of(ZoneId.java:357)
        at org.threeten.bp.ZoneId.of(ZoneId.java:285)
        at org.threeten.bp.ZoneId.systemDefault(ZoneId.java:244)
        at org.threeten.bp.Clock.systemDefaultZone(Clock.java:137)
        at org.threeten.bp.LocalDate.now(LocalDate.java:165)
  </code></pre>
  
  <p>The same line of code works well in another java project I have, which uses the native java.time library.  </p>
  
  <p>I searched for a possible solution but couldn't find anything useful: one solution suggested I need to use another jar that includes the time-zone rules and other suggested that there might be two or more ThreeTenBP-libraries inside the classpath.<br>
  Those cases don't match my case.</p>
  
  <p>Inside the <code>build.gradle</code> file, at the dependencies section, I've tried few configurations:  </p>
  
  <ul>
  <li>At first, I used - <code>compile 'com.jakewharton.threetenabp:threetenabp:1.0.3'</code></li>
  <li>Then, I tried -
  <code>compile 'org.threeten:threetenbp:1.0.3'</code></li>
  <li>After that, I tried -
  <code>compile 'org.threeten:threetenbp:1.3.1'</code></li>
  <li>Currently, I use <code>compile 'org.threeten:threetenbp:1.3.2'</code></li>
  </ul>
  
  <p>I don't know what is wrong with that line of code and how to fix it.<br>
  The <code>LocalDate.now()</code> and <code>LocalTime.now()</code> methods should work without specifying a time zone.</p>