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JavaIntermediate#object#hashmap
JavaBeginner#object#fundamentals
What is the difference between == and equals() when comparing objects that don't override equals()?
If a class doesn't override equals(), it inherits Object's implementation, which behaves identically to ==, comparing references rather than logical content.
Example
class Point { int x, y; }
Point p1 = new Point();
Point p2 = new Point();
p1.equals(p2); // false, same as p1 == p2, since equals() isn't overridden