Determines whether this charset is a superset of the given charset. A charset C1 contains charset C2 if every character representable by C2 is also representable by C1. This means that lossless conversion is possible from C2 to C1 (but not necessarily the other way round). It does not imply that the two charsets use the same byte sequences for the characters they share.

Note that this method is allowed to be conservative, and some implementations may return false when this charset does contain the other charset. Android's implementation is precise, and will always return true in such cases.

[Android Documentation]