title: sbt - Building Spark takes too much time
body: <p>I am trying to build Apache Spark from the modified source using sbt. I actually have made just a few changes to the spark core, all the other modules remained untouched. However, each time I build spark by using the command </p>
  
  <pre><code>sbt/sbt assembly
  </code></pre>
  
  <p>it compiles and resolves all of the dependencies again. The application that I run using modified Spark source is also using only the core Spark functionality, nothing fancy. Is there a way to make spark recompile only the modified, store resolved dependencies in cache or any other way for that matter would could speed up the jar building process.</p>