i need the codes of these exercises in java pls

Exercise \# 3: (The Triangle class) Design a class named Triangle that extends SimpleGeometricObject. The class contains: Three double data fields named side1, side 2 , and side 3 with default values 1.0 to denote three sides of a triangle. - A no-arg constructor that creates a default triangle. - A constructor that creates a triangle with the specified side1, side2, and side 3. - The accessor methods for all three data fields. - A method named getArea 0 that returns the area of this triangle. - A method named getPerimeterO that returns the perimeter of this triangle. - A method named toString() that returns a string description for the triangle. The toString() method is implemented as follows: return "Triangle: side = " + side 1+ " side 2= " + side 2+ " side 3= " + side 3