Answer by i_am_zero for How does the Java 'for each' loop work?

As defined in JLS for-each loop can have two forms:

1. If the type of Expression is a subtype of Iterable then translation is as:

   List<String> someList = new ArrayList<String>();
   someList.add("Apple");
   someList.add("Ball");
   for (String item : someList) {
       System.out.println(item);
   }
   
   // IS TRANSLATED TO:
   
   for(Iterator<String> stringIterator = someList.iterator(); stringIterator.hasNext(); ) {
       String item = stringIterator.next();
       System.out.println(item);
   }
   

2. If the Expression necessarily has an array type T[] then:

   String[] someArray = new String[2];
   someArray[0] = "Apple";
   someArray[1] = "Ball";
   
   for(String item2 : someArray) {
       System.out.println(item2);
   }
   
   // IS TRANSLATED TO:
   for (int i = 0; i < someArray.length; i++) {
       String item2 = someArray[i];
       System.out.println(item2);
   }
   

Java 8 has introduced streams which perform generally better. We can use them as:

someList.stream().forEach(System.out::println);
Arrays.stream(someArray).forEach(System.out::println);