Sets all of the data defining the line segment.
"line2D_var" is a variable referencing a Line2D object. | 
        
"line2D_var" is a variable referencing a Line2D object. | 
        
| Type | Description | 
| boolean | Returns true if redefining the line is successful | 
| Name | Type | Description | 
| startPoint | Point2D | The start point of the line | 
| endPoint | Point2D | The end point of the line |