Indicates whether some other object is "equal to" this one.
equals method implements an equivalence relation
on non-null object references:
trueif and only if
y, multiple invocations of
trueor consistently return
false, provided no information used in
equalscomparisons on the objects is modified.
equals method for class
the most discriminating possible equivalence relation on objects;
that is, for any non-null reference values
y, this method returns
true if and only
y refer to the same object
x == y has the value
Note that it is generally necessary to override the
method whenever this method is overridden, so as to maintain the
general contract for the
hashCode method, which states
that equal objects must have equal hash codes.
|the reference object with which to compare.|
true if this object is the same as the obj