Based on code from: https://www.tutorialspoint.com/design_pattern/factory_pattern.htm

public interface Shape {
     void draw();
}

public class Rectangle implements Shape {

     @Override
     public void draw() {
          System.out.println("This is the Rectangle draw() method.");
     }
}

public class Square implements Shape {

     @Override
     public void draw() {
          System.out.println("This is the Square draw() method.");
     }
}

public class Circle implements Shape {

     @Override
     public void draw() {
          System.out.println("This is the Circle draw() method.");
     }
}

public abstract class ShapeFactory {

     //use getShape method to get object of type shape
     public Shape getShape(String shapeType){
          if(shapeType == null){
                return null;
          }
          if(shapeType.equalsIgnoreCase("CIRCLE")){
                return new Circle();
          } else if(shapeType.equalsIgnoreCase("RECTANGLE")){
                return new Rectangle();
          } else if(shapeType.equalsIgnoreCase("SQUARE")){
                return new Square();
          } else if(shapeType.equalsIgnoreCase("ROUND SHAPE")){
		    return new Oval();
	    }
          return null;
     }
}

public class FactoryPatternDemo {
     public static void main(String[] args) {
          ShapeFactory shapeFactory = new ShapeFactory();

          //get an object of type Circle.
          Shape shape1 = shapeFactory.getShape("ROUND SHAPE");

          //call Circe's draw method
          shape1.draw();

          //get an object of type Rectangle
          Shape shape2 = shapeFactory.getShape("RECTANGLE");

          //call Rectangle's draw method
          shape2.draw();

          //get an object of type Square
          Shape shape3 = shapeFactory.getShape("SQUARE");

          //call Square's draw method
          shape3.draw();
     }
}

Alternatively, make ShapeFactory abstract and have TriangleShapeFactory and a RectangleShapeFactory for drawing different sets of shapes.