Groovy 一些小细节

http://docs.groovy-lang.org/latest/html/gapi/groovy/transform/Field.html

[Java] Annotation Type Field

• groovy.transform.Field

• Variable annotation used for changing the scope of a variable within a script from being within the run method of the script to being at the class level for the script.

  The annotated variable will become a private field of the script class. The type of the field will be the same as the type of the variable. Example usage:

   @Field List awe = [1, 2, 3]
   def awesum() { awe.sum() }
   assert awesum() == 6
   

  In this example, without the annotation, variable awe would be a local script variable (technically speaking it will be a local variable within the run method of the script class). Such a local variable would not be visible inside the awesum method. With the annotation, awe becomes a private List field in the script class and is visible within the awesum method.