NullPointerException when using ToBuilder and Singular on List-based Property

[HartmutLuttermann]

Having following class definition

@Value
@Builder(toBuilder = true)
public class ValueObject{

    @Singular(value = "value")
    private List<String> values;
}

and using following statement

new ValueObject(null).toBuilder();

throws NullPointerException in method toBuilder()

java.lang.NullPointerException
	at java.util.ArrayList.addAll(ArrayList.java:577)
	at <package>.ValueObject$ValueObjectBuilder.values(ValueObject.java:10)

In my opinion this is an error in the implementation of the setter-method of the ValueObjectBuilder. A non-null-check only will fix this:

public ValueObject.ValueObjectBuilder values(final Collection<? extends String> values) {
            if (this.values == null) this.values = new ArrayList<String>();
           // added: check on non-null values
            if (values != null)
                  this.values.addAll(values);
            return this;
        }

[brokenbeatnik]

I'm also seeing this issue.

[oyku-gencay]

Same here. I've got a private constructor annotated with Builder with toBuilder true.

[rzwitserloot]

Duplicate of #1324 – the suggested fix is not acceptable; calling .foos(null) silently doing nothing is not a sound plan. A fix for this problem is forthcoming.