How to implement a method for comparing objects to determine their equality in a programming language?

In Java, to determine object equality, the equals(Object obj) method of the Object class is usually overridden. This method should compare the significant fields of objects to determine if they are considered equal.

Main rules when overriding equals:

• Check that the passed object is not null and belongs to the same class.
• Compare all fields that influence equality.
• The method should be symmetric, reflexive, and transitive.

Example implementation:

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

It is also recommended to override hashCode() so that objects considered equal by equals have the same hash code.