Java – HashMap means that even if it does exist, the key does not exist

I have an interesting problem. I'm sure it's HashMap's fault Consider the following debugging code (AMAP is the HashMap and key is the value passed to this method)

System.out.println("getBValues - Given: " + key);
System.out.println("getBValues - Contains Key: " + AMap.containsKey(key));
System.out.println("getBValues - Value: " + AMap.get(key));
for(Map.Entry<A,HashSet<B>> entry : AMap.entrySet()) {
    System.out.println("getBValues(key) - Equal: " + (key.equals(entry.getKey())));
    System.out.println("getBValues(key) - HashCode Equal: "+(key.hashCode() == entry.getKey().hashCode()));
    System.out.println("getBValues(key) - Key: " + entry.getKey());
    System.out.println("getBValues(key) - Value: " + entry.getValue());
}

Now I insert a channel and value into this map Later, I tried to get the value with get () and run the debugging code. In my example, I gave this output:

getBValues - Given: Channel(...)
getBValues - Contains Key: false <--- Doesnt contain key?!
getBValues - Value: null   <--- Null (bad)
getBValues(key) - Equal: true <--- Given key and AMap key is equal
getBValues(key) - HashCode Equal: true
getBValues(key) - Key: Channel(Same...)
getBValues(key) - Value: []    <--- Not null (This is the expected result)

As you can see, getting the key directly from the HashMap doesn't work, but the loop gets the exact same key through I, which means it can't find it in get() My question is what causes this? How can get() not find the existing key?

I'll provide some sample code, but I don't seem to be able to reproduce it independently

Any suggestions that might cause this problem?

Solution

From what I have seen, we still do not rule out whether it is related to invariance

aMap.put(key,value);
key.setFieldIncludedInHashCodeAndEquals(25);

Then you'll get the results from it

To exclude this, show us more code or add it to the for loop in the example above

System.out.println(aMap.get(entry.getKey()));

In addition, use the debugger In this way, you can see whether your object is in the correct bucket