Question

Code:

public class MyClass {
 private Map<Integer,String> myMap=new HashMap<Integer, String>();
 ...........................


void methodFillMap(){
   myMap.put(.....);

 .....................
}

}

What is correct:

 void methodFillMap(){
 myMap.clear();
 myMap.put(.....);

 .....................
 }

or

void methodFillMap(){
myMap=null;
myMap.put(.....);

 .....................

}
or better

void methodFillMap(){
  myMap=new HashMap<Integer, String>();
  myMap.put(.....);

  .....................
}

Answer 1

The last one is the best one if you not coding for a system with very limited memmory then it’s the first one that is best

1. In the first case you have to clear the hashtabel whitch takes some computation.
2. The secound won’t even work since you just got a null reference and not a hashmap.
3. In the third case you just throw away the old hashmap and let the garbage collector handle the old one.