G/radient Specifications: Missing The Missing class is a utility class. In addition to the obvious specifications illustrated in the UML class diagram, the Missing class must satisfy the following specifications. 1. The default double value of a missing value must be 0 . O. 2. The method doubleValue (Double number) must return the double value of the Double parameter unless it is nul, in which case it must return the default double value of a missing value. 3. The method doubleValue (Double number, double missingValue) must return the double value of the Double parameter unless it is null, in which case it must return missingValue