collection foreach java 8 example

Example 1: java lambda iterate list

List<String> items = new ArrayList<>();
items.add("A");
items.add("B");
items.add("C");
items.add("D");
items.add("E");

//lambda
//Output : A,B,C,D,E
items.forEach(item->System.out.println(item));

//Output : C
items.forEach(item->{
	if("C".equals(item)){
		System.out.println(item);
	}
});

//method reference
//Output : A,B,C,D,E
items.forEach(System.out::println);

//Stream and filter
//Output : B
items.stream()
	.filter(s->s.contains("B"))
	.forEach(System.out::println);

Example 2: loop in java 8

List<Integer> data = new ArrayList<>();

//Indexed Loop
for(int i = 0,size=data.size();i<size;i++){
	System.out.println(data.get(i));  
}

//For each loop
for(Integer element : data){
	System.out.println(element);
}

//Using forEach
data.forEach(System.out::println);

//Using Stream
data.stream().forEach(System.out::println)
  
//While loop
int i = 0;
while(i<data.size()){
	System.out.println(data.get(i++));  
}