How to determine the number of fields set on an object in Java

I'm not sure if I can do this, but I say I have this object:

public class SomeObject
{
    private String field1;
    private String field2;
    ....

    //Blah Blah getters and setters for all fields
}

I want to know how many of these fields are not empty My specific object has 40 fields, so I really don't want the if block to check each of the 40 fields separately I thought I could do this with reflection in some way? But I really don't know what I'm doing Just walk through all the fields and check their values

For the people there, I don't think it's easy

Solution

Yes, you can do this with reflection:

SomeObject objectReference = ...; // The object you're interested in
Class clazz = SomeObject.class;
int nullCount = 0;
for (Field field : clazz.getDeclaredFields())
{
    field.setAccessible(true);
    if (field.get(objectReference) == null)
    {
        nullCount++;
    }
}

(except for various exceptions, permissions, etc.)

It feels a bit like a hacker... To be honest, it's a bit strange You definitely need all 40 fields. Do you need to treat them as separate fields instead of (for example) arrays?