Using pattern matching with switch constructs

The switch statement seems to be one of the best constructs that can use pattern matching. At present, a switch construct can match primitive literal values (excluding long, float, and double), String, and enum constants.

If a case label can specify a pattern, the code in the preceding section (the one that uses multiple instances of object checking and value extraction) can be modified as follows:

void dyingFish(Object obj) { 
    switch (obj) { 
        case Ocean o:   System.out.println(o.getBottles()); 
                        break; 
        case Sea sea:   System.out.println(sea.getDeadFish()); 
                        break; 
        case River riv: if (riv.getPlasticBags() > 100) { 
                            System.out.println("Humans enjoy! Fish die!"); 
                        } 
                        break...