Uses of Interface

Packages that use PlayerProfile
The root package of the Bukkit API, contains generalized API classes.
Classes relevant to bans.
Classes used to manipulate the voxels in a world, including special states.
Interfaces for non-voxel objects that can exist in a world, including all players, monsters, projectiles, etc.
The interfaces used when manipulating extra data can can be stored inside item stacks.
Classes relevant to player profiles.