Research on Java collection classes

Test code:

int initialcapacity = 16;
float loadfactor = 0.75f;
hashmap<string,string> HashMap = new hashmap<> (initialcapacity,loadfactor);
System.out.println (Hashmap.put ("1", "V1"));
System.out.println (Hashmap.put ("1", "V2"));

Iterator<string> it = Hashmap.keyset (). Iterator ();
while (It.hasnext ()) {
System.out.println (Hashmap.get (It.next ()));
}

　　

2. //system default initial capacity, must be 2 of the power of N, this is due to optimization considerations
4. static final int default_initial_capacity = 16;
8. //system default maximum capacity
10. static final int maximum_capacity = 1 << 30;
14. //system default load factor, which can be specified in the constructor
16. static final float default_load_factor = 0.75f;
20. //table for storage, length can be adjusted, and must be 2 n power
22. transient entry[] table;
26. the Key-value map number of the current map, which is the current size
28. transient int size;
32. //Threshold value
34. int threshold;
38. //hash Table load factor
40. final float loadfactor;
44. //used to ensure that iterators are used, HashMap is not changed
46. transient volatile int modcount;
    

HashMap two parameter initialcapacity (Initialize container size), Loadfactor (load factor) in the constructor method

Research on Java collection classes