boon/src/main/java/org/boon/criteria/ObjectFilter.java
public static Criterion notIn( final Object name, final Object... values ) {
        return new Criterion<Object>( name.toString(), Operator.NOT_IN, values ) {

            @Override
            public boolean resolve( Object owner ) {


                Object fieldValue = fieldValue();
                if ( value == null ) {
                    return false;
                }
                return !valueSet().contains( fieldValue );
            }
        };
    }
public static Criterion notIn( final Object name, final Object... values ) {
        return new Criterion<Object>( name.toString(), Operator.NOT_IN, values ) {

            @Override
            public boolean resolve( Object owner ) {


                Object fieldValue = fieldValue();
                if ( value == null ) {
                    return false;
                }
                return !valueSet().contains( fieldValue );
            }
        };
    }
This has to convert values to field type.