I haven't dealt with Java in the last ... 12 years (and only very little back then), but I liked the convention of naming Interfaces after adjectives. In Java,

I haven't dealt with Java in the last ... 12 years (and only very little back then), but I liked the convention of naming Interfaces after adjectives. In Java, it would be named Sortable, and element types of a sortable collection would implement Comparable<T>.