Collections

• Map entry

    Map<String, String> map = new HashMap<String, String>();
    for (Map.Entry<String,String> entry : gfg.entrySet())  
          System.out.println("Key = " + entry.getKey() + 
                           ", Value = " + entry.getValue()); 
  

• Loops

  for(String str : strArray) {
      System.out.println(str);
  }
  

• Array to list

  List<Integer> list = Arrays.asList(integerArray)
  

  List to Array

  int[] arr = list.toArray();
  

• Streams

   Stream<Integer> stream = list.stream();
   List<Integer> evenNumbersList = list.stream()
                                  .filter(i -> i%2 == 0)
                                  .collect(Collectors.toList());
  

  memberNames.stream().filter((s) -> s.startsWith("A"))
                   .map(String::toUpperCase)
                   .forEach(System.out::println);
  

  map.stream().sorted().map(String::toUpperCase).collect(Collectors.toList());
      
      
  // sort and println
  memberNames.stream().sorted()
                  .map(String::toUpperCase)
                  .forEach(System.out::println);