Common operation methods and traversal of Set objects

Set<String> set = new HashSet<String>();
/**
* The common operation methods of set are:
* add() adds elements to the set clear() clears the set elements
* contains() judges whether the set contains a certain one Element
* isEmpty() determines whether it is empty
* iterator() is used for recursive collection, returning an Iterator object
* remove()
* size()
* Implementing the Set interface includes HashSet and TreeSet, of which TreeSet can be sorted by default (integer data type )
*/
set.add("Xiaomi");
set.add("Huawei");
set.add("Samsung");
set.add("Lenovo");
set.add("Apple");
// Enhanced for loop
for(String s:set){
System.out.println(s);
}
//
Iterator iterator = set.iterator();
while(iterator.hasNext()){
String st = (String)iterator .next();
System.out.println(st);
}