例句與造句

1. Groovy features not available in Java include both static and dynamic typing ( with the keyword def ), operator overloading, native syntax for lists and associative arrays ( maps ), native support for regular expressions, polymorphic iteration, expressions embedded inside strings, added helper methods, and the safe navigation operator ? . to check automatically for null pointers ( for example, variable ? . method ( ), or variable ? . field ).
2. It's difficult to find safe navigation operator in a sentence. 用safe navigation operator造句挺難的