Can you explain the main rules for overriding the equals method in Java?

Main rules for overriding the equals method in Java:

1. Reflexivity: an object must be equal to itself (x.equals(x) == true).
2. Symmetry: if x.equals(y) == true, then y.equals(x) should also be true.
3. Transitivity: if x.equals(y) == true and y.equals(z) == true, then x.equals(z) == true.
4. Consistency: multiple calls to equals with the same objects should return the same result.
5. Comparison with null: x.equals(null) should return false.

When overriding equals, it is also common to override hashCode so that objects equal according to equals have the same hashCode.

Example:

@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) && field2 == other.field2;
}