[Solved] Why doesn’t my hashmap work? My object has the property that hashCode() equality implies equals(…) equality [closed]

Question

You can assume that I’m modifying a field of the object after I add the object to the HashMap.

That right there is why.

Note: great care must be exercised if mutable objects are used as map keys. The behavior of a map is not specified if the value of an object is changed in a manner that affects equals comparisons while the object is a key in the map.

“Not specified” means “may not to work”, so you should not be surprised when it doesn’t work.

Accepted Answer

You can assume that I’m modifying a field of the object after I add the object to the HashMap.

That right there is why.

Javadoc says:

Note: great care must be exercised if mutable objects are used as map keys. The behavior of a map is not specified if the value of an object is changed in a manner that affects equals comparisons while the object is a key in the map.

“Not specified” means “may not to work”, so you should not be surprised when it doesn’t work.