how to handle nulls gracefully in Java

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Avoiding != null statements 58 answers

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Apache commons-lang3 offers this:

b.setC(ObjectUtils.defaultIfNull(a.getC(), b.getC()));

But I have to admit that I'm not sure if this would really be an improvement.

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You could make a method using var args that checks all the args for your if statement:

public boolean argsNotNull(Object ... objs) {
    boolean b = true;
    for(Object o : objs) {
        if(o == null) {
            b = false;
            break;
        }
    }
    return b;
}

Then use it like this:

if(argsNotNull(a)) {
    Object c = a.getC();
    if(argsNotNull(b, c)) { // A null 'c' object may be valid here, depends on your logic
        b.setC(c);
    }
}

Since this method uses var args you can feed it as many args as you want, but it will not work with primitives in its current state.

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Is the bC value supposed to exactly reflect what is in aC ? In that case if aC is null then bC whould be null, and you don't really need a null check.

Otherwise, to avoid curley braces you could do something like this :

b.setC((a.getC() == null) ? b.getC() : a.getC());

This assumes that the getter and setter from b match up exactly. If C from a is null then setC() from getC() which effectively does nothing.

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