put
Associates key with value, replacing the value for an equal existing key.
Replacement retains the original stored key and does not invalidate iterators. Inserting a new key increases size, may grow the table and invalidates existing iterators. A null result can also mean that the previous value was null; use containsKey before mutation to distinguish absence.
Return
the previous value, or null when the key was absent.
Parameters
key
key to insert or update, with stable equality and hashing while stored.
value
value to associate with the key.
Throws
if inserting a new key exceeds the supported size or bucket capacity.