Wildcard capture exactly what is the use? Since there is a why use swap to call swapHelper swapHelpe-CodePudding

Feeling "Java core technology volume I" this place is a bit confused,

 
Public static void swap (Pair<?> P) {

SwapHelper (p); 
} 
Public static & lt; T> Void swapHelper (Pair P) {

T T=p.g etFirst (); 

P. etFirst (p.g etSecond ()); 

P. etSecond (t); 

}

P - 335, said the inevitable

 
A public static void maxminBonus (Manager [], Pair<? Super Manager> Resu1t) {

MaxminBonus (a, result); 

PairAlg. Swap (result);//OK - swapHelper captures wildcard type 

}

Turning the program list becomes

 
A public static void maxminBonus (Manager [], Pair<? Super Manager> Resu1t) {

MaxminBonus (a, result); 

PairAlg. SwapHelper (result);//OK - swapHelper captures wildcard type 

}