java - How to Shallow Copy Array list with full working example -

as java noob spend of day trying find solution easy apply deep copy arraylist. thought had found , posted code example here. found comments below wrong , had produced shallow copy. problem being didn't understand meant deep copy. have edited title , question. code works , might still useful me starting climb learning curve.

the best answer find use foreach statement cycle through contents of 1 array , copy them another. prove works, below small complete test program demonstrate.

package test;  import java.util.arraylist; public class arraylistcopy { public static void main(string[] args){     system.out.println("running array copy test");      arraylist < string > arrayfrm;  //define 2 arrays     arraylist < string > arrayto;      arrayfrm = new arraylist<string>(3);  //load 1 of them     arrayfrm.add("one");     arrayfrm.add("two");     arrayfrm.add("three");      arrayto = new arraylist <string>(3);  //create array copy     arrayfrm.foreach(item->arrayto.add(item));  // deep copy      arrayto.foreach(item->system.out.println(item));  //make sure works }  } 

in code, deep copy completed 2 lines of code. use size of old array set size of new array. use foreach loop complete deep copy.

        newarray  = new arraylist <string>( oldarray.size());          oldarray.foreach(item->newarray.add(item)); 

i haven't tried multi-dimensional array. use other data types, change string meet requirements.