The Performance Comparison of Different traversal methods of ArrayList is actually not much worse. The performance comparison of arraylist

The Performance Comparison of Different traversal methods of ArrayList is actually not much worse. The performance comparison of arraylist

// RadomAcess interface .. I traversal ratio .. fast loop, @ more see comments for interface RandomAcess import java. util. arrayList; import java. util. iterator; import java. util. list; public class ListPerformanceTest {public static void main (String [] args) {List <String> list = new ArrayList <> (); for (int I = 0; I <Integer. MAX_VALUE/200; I ++) {list. add ("1");} long d1 = System. currentTimeMillis ();/******************* fas Test ********************** // for (int I = 0, n = list. size (); I <n; I ++) {// list. get (I ); ///}/**************** second fastest due to each loop wocould get the list size ******** * *************** // for (int I = 0; I <list. size (); I ++) {// list. get (I ); ///}/***************** not know why this is faster than the last ********** * ************* // for (Iterator <?> It = list. iterator (); it. hasNext ();) {// it. next (); //} // for (String s: list) {// if (s! = Null) {// continue; //} System. out. println ("Times (MS):" + (System. currentTimeMillis ()-d1 ));}}