Removes the specified element from this set if it is present.
More formally, removes an element {@code e} such that
<tt>(o==null ? e==null : o.equals(e))</tt>,
if this set contains such an element. Returns {@code true} if
this set contained the element (or equivalently, if this set
changed as a result of the call). (This set will not contain the
element once the call returns.)
@param o object to be removed from this set, if present
@return {@code true} if this set contained the specified element
@throws ClassCastException if the specified object cannot be compared
with the elements currently in this set
@throws NullPointerException if the specified element is null
and this set uses natural ordering, or its comparator
does not permit null elements
Removes the specified element from this set if it is present. More formally, removes an element {@code e} such that <tt>(o==null ? e==null : o.equals(e))</tt>, if this set contains such an element. Returns {@code true} if this set contained the element (or equivalently, if this set changed as a result of the call). (This set will not contain the element once the call returns.)
@param o object to be removed from this set, if present @return {@code true} if this set contained the specified element @throws ClassCastException if the specified object cannot be compared with the elements currently in this set @throws NullPointerException if the specified element is null and this set uses natural ordering, or its comparator does not permit null elements