Can objects of different classes be considered equal if all their fields match?

In Java, objects of different classes are usually not considered equal, even if all their fields have the same values. The equals() method by default compares references (i.e., checks if variables point to the same object). If you override equals(), the comparison logic can consider fields, but typically objects of the same class or compatible classes are compared.

Comparing objects of different classes with the same fields can lead to unexpected results and violate the contracts of equals() and hashCode(). Therefore, it is recommended to consider objects equal only if they belong to the same class (or compatible classes) and have the same field values.

Example of overriding equals() with a class check:

@Override
public boolean equals(Object obj) {
    if (this == obj) return true;
    if (obj == null || getClass() != obj.getClass()) return false;
    MyClass other = (MyClass) obj;
    return Objects.equals(field1, other.field1) &&
           Objects.equals(field2, other.field2);
}