Part 1. Create a class GradedActivity that has two attributes: score and weight (both doubles). Supply a constructor that allows one to set both the score and weight, AND one that allows one to set just the weight (in which case the score defaults to 0). Provide get and set methods: enforce the restriction that the grade must be between 0 and 100 (inclusive) and the weight must be between 0 and 1 (exclusive); if either is not within range, throw an exception. In addition supply a toString method and a method, getGrade( ) that returns a char: A, B, C, D, F; use the usual meaning of these grades and round up any grades that are nn.5 or higher.