write a java program $$ Make a Rectangle class containing

$$ define a constant which can be used as a default value for the length and width variables of the class

$$ declare length and width data members with private keyword

$$ define a default constructor

$$ define a constructor with two arguments

$$ define a setLength$()$ method

$$ define a setWidth$()$ method

$$ define a setLength$\_$Width$()$ method $($it will set both private variables of class at the same time$)$

$$ define a getLength$()$ method

$$ define a getWidth$()$ method

$$ findArea$()$

$$ findPerimeter$()$

$$ define a toString$()$ method $($overriding toString$()$ method of Object class$)$

$$ define an equals$()$ method $($overriding equals$()$ method of Object class$)$