Java ArrayList Copy Changing Original Value -

i have copied arraylist want keep original values of source arraylist.

if change first item of source arraylist, automatically chnages first item value of new arraylist.

i used few code blocks couldn't solve problem.

arraylist<sicilbakiye> resultcopy = new arraylist<sicilbakiye>(); resultcopy.addall(result);  // 1.method  resultcopy=result.clone();  // 2.method  resultcopy=result;  // 3.method 

if change :

result.get(0).setid(5); 

this automatically changes :

resultcopy.get(0).getid() // return 5 

how can solve ? ideas

let's have @ 3 methods provided , address problem:

arraylist resultcopy = new arraylist();
resultcopy.addall(result); // 1.method

this creates empty array list , adds elements result copy. change result (e.g. adding new element or removing one) not reflected in copy.

resultcopy=result.clone(); // 2.method

that same above, @ least of standard implementation used - copy created inside of clone() , returned.

resultcopy=result; // 3.method

this assigns instance result references resultcopy, i.e. have 2 references same list. change made result reflected resultcopy , vice versa.

now actual problem:

result.get(0).setid(5); does not change result element inside result. see change in resultcopy.

it's same if put 2 courses @ school. if leave 1 you'll still in other , vice versa. if age changes (which ;) ) teacher in each course same answer.

what you're after called deep copy: copy list elements inside list. if reference other objects might have copy them - stop depends on requirements , structure of objects.

to create deep copies of objects either implement , call clone() needed, use library clones via reflection (e.g. apache commons beanutils) or use mapping library (e.g. dozer, mapstruct, etc.).