dongwei fu thinks this is interesting: Immutable From Chapter 3. Simple Groovy datatypes from Groovy in Action, Second Edition by Dierk König and Paul King with Guillaume Laforge, Hamlet D'Arcy, Cédric Champeau, Erik Pragt, and Jon Skeet Publisher: Manning Publications Released: June 2015 Note 重新实现例如equal方法 Share this highlight http://www.safaribooksonline.com/a/groovy-in-action/3655354/ Twitter Facebook Google Plus Email Get Instant Access Now Start a Free Trial Learn about Safari for Business Have an account? Sign in. Minimise Unlock the rest of Groovy in Action, Second Edition and 30,000 other books and videos By clicking this box, you confirm that you have read and agree to the terms and conditions of our Membership Agreement, and you understand that when your trial period ends, you will be required to provide billing information if you wish to continue using the service. Unlock the rest of this book Start a Free 10-Day Trial loading Learn about Safari for Business Have an account? Sign in.