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 ));}}