The interface SomeInterface cannot define an initializer
初始化块
site:docs.oracle.com initializer
http://docs.oracle.com/javase/specs/jls/se8/html/jls-8.html
区别：
Instance initializers are blocks of executable code that may be used to help initialize an instance when it is created.
Static initializers are blocks of executable code that may be used to help initialize a class.