Summary
-------

Add an explicitly declared no-arg constructor to `java.lang.Number` to avoid use of the default constructor.

Problem
-------

Default constructors are inappropriate for well-documented APIs.

Solution
--------

Add an explicit (trivial) constructor to `java.lang.Number`.

Specification
-------------

     public abstract class Number implements java.io.Serializable {
         /**
    +     * Constructor for subclasses to call.
    +     */
    +    public Number() {super();}
    +
    +    /**