Lower-bounded wildcards show up when you want to specify a callback object, such as a comparator, or a data structure into which you are going to place a value.

当您希望指定一个回调对象(例如一个比较器)或存放某个值的数据结构，可以使用下限通配符。

youdao

Lower-bounded wildcards show up when you want to specify a callback object, such as a comparator, or a data structure into which you are going to place a value.

当您希望指定一个回调对象(例如一个比较器)或存放某个值的数据结构，可以使用下限通配符。

youdao