Question

What is the best way to override equals method in java to compare more than one field? For example, I have 4 objects in the class, o1, o2, o3, o4 and I want compare all of them with the passed object to the equals method.

if (o1 != null && o2 != null && o3 != null && o4 != null && obj.o1 != null
    && obj.o2 != null && obj.o3 != null && obj.o4 != null
    && o1.equals(obj.o1) && o2.equals(obj.o2) && o3.equals(obj.o3) && o4.equals(obj.o4)) {
    do something
}

The problem with this code is that it’s not clear and can’t be modified easily specially if we have more fields. Is there a better way to achieve that?

Answer 1

A cheap way would be to do:

Arrays.asList(o1, o2, o3, o4).equals(Arrays.asList(obj.o1, obj.o2, obj.o3, obj.o4));