I noticed in the source code for HashMap it lists the equals method as final. Why is it that when I override it I do not get a compile error?
public class Test extends HashMap<Object, Object> {
@Override
public boolean equals(Object o) {
return false;
}
}
Java HashMap equals method:
public final boolean equals(Object o) {
开发者_运维问答 if (!(o instanceof Map.Entry))
return false;
Map.Entry e = (Map.Entry)o;
Object k1 = getKey();
Object k2 = e.getKey();
if (k1 == k2 || (k1 != null && k1.equals(k2))) {
Object v1 = getValue();
Object v2 = e.getValue();
if (v1 == v2 || (v1 != null && v1.equals(v2)))
return true;
}
return false;
}
That's the equals method for HashMap.Entry
, not HashMap
itself - look at how it's trying to use the reference passed into it as a Map.Entry
.
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