title: What's the syntax to create a Serializable Groovy Class for Jenkins Workflow/Pipeline
body: <p>Working with Jenkins Workflow Groovy, I'm running into Serialization errors when trying to create objects for a dead simple class.  What kind of syntactic sugar is required to pass the serializable test?  The following code is failing. Adding the @Serializable line fails with "class java.io.Serializable is not an annotation in @java.io.Serializable"</p>
  
  <pre><code>//@Serializable 
  class TestClass { 
      def hello() { 
          println "halloooo" 
      } 
  } 
  def myobj = TestClass.newInstance() 
  node () { 
      myobj.hello() 
  }
  </code></pre>