java - list value replaced when set value to the sam object -


list value replaced when set value list. please me .

public void testvalue(){         invintc1 = new arraylist<>();         invintc2 = new arraylist<>();          invintc invin = new invintc();         invin.setinvintckey("1234");         invin.setinvintcqty(1); // set value in here         invintc1.add(invin);          invintc invin2 = invintc1.get(0);         invin2.setinvintcqty(5); // , when set value again, value invintc1 replaced 5         invintc2.add(invin);     }

you have one object here - 1 instance of invintc.

the values in both array lists refer same object, changes made object visible via both lists.

as real world example, suppose write down home address on 2 pieces of paper, , give 1 piece of paper joe , 1 fred. joe goes , paints front door red... fred visits house. of course he'll see red front door. same thing happening in code.

if want 2 independent objects, need create 2 independent objects:

invintc invin = new invintc(); invin.setinvintckey("1234"); invin.setinvintcqty(1); invintc1.add(invin);  invintc invin2 = new invintc(); // copy key 1 object other invin2.setinvintckey(invin.getinvtckey()); // set different quantity invin2.setinvintcqty(5); invintc2.add(invin);

it's vitally important understand how objects , references work in java. suggest hold of book explains in detail.

(i'd encourage rethink names more friendly.)


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