http://blog.ik.am/#/entries/293 のやつ

Steam.java

public class Stream {

	public static void main(String[] args) {

		Optional<String> result = Optional.empty();
		for(String lang : Arrays.asList("C++", "Go", "Java", "Python", "Ruby")){
			String _lang = lang.toUpperCase();
			System.out.println("toUppercase(" + _lang + ")");
			System.out.println("length(" + _lang + ")");
			if(_lang.length() == 4){
				result = Optional.of(_lang);
				break;
			}
		}
	}
}

Stream2.java

/** http://itpro.nikkeibp.co.jp/atcl/column/14/224071/092600006/ のやつ */
public class Stream2 {
	public static void main(String[] args){
		for(int x : Arrays.asList(0,1,2,3,4,5)){
			System.out.println("filter: " + x);
			if(x%2==0){
				System.out.println("map: " + x);
				int _x = x/2;
				System.out.println("forEach: " + _x);
			}
		}

	}
}