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PODealing with ArrayList and pass by reference
 

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    <p>I'm using a arraylist to add states(the board state for the 8 puzzle). My problem is when I get the children of the state it changes the values stored in my array list. I'm assuming this is because ArrayList just stores pointers to the objects and not the values themselves. In order to fix this I create a new object every time before I store it into the ArrayList but I'm still having the same problem.</p> <p>I will also try to follow naming conventions more often thanks for the tip.</p> <pre><code> private ArrayList&lt;int[][]&gt;VisitedBoard; if(RuleNumber ==2){ //Here is my problem. This will change what is stored in VistedBoards NextState = new State(FireRule.Rule2(WM.get_Board()));//Fire Rule for(int j=0;j&lt;VisitedBoards.size();j++){ //Meaning this will always be true if(Arrays.equals(VisitedBoards.get(j), NextState.get_Board())){ Loop =true; //Loop to previous state } if(j==VisitedBoards.size()-1 &amp;&amp; Loop ==false){ //If the next state is not any previously visited NotALoop =true; VisitedBoards.add(NextState.get_Board()); WM.set_Board(NextState.get_Board()); } } } public int[][] Rule2(int [][] Board){//The FireRule Class Find_BlankLocation(Board); int temp; State NewState; temp = Board[BlankLocation[0]-1][BlankLocation[1]]; Board[BlankLocation[0]-1][BlankLocation[1]] = 0; Board[BlankLocation[0]][BlankLocation[1]] = temp; NewState = new State(Board); return Board; } public class State { //State class private int[][] Board; private int[][] Goal; private Boolean GoalFound; public State(int[][] Start, int[][] goal){ Board = Start; Goal = goal; GoalFound=false; } public State(int[][] NewState){ Board=NewState; } public int[][] get_Goal(){ return Goal; } public int[][] get_Board(){ return Board; } public void set_Board(int[][] board){ Board = board; } public Boolean get_GoalFound(){ return GoalFound; } </code></pre> <p>}</p>
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    1. COIt's really hard to follow your code because you don't follow naming conventions. Class names should be capitalized, variable names should be lowercase. Underscores are not used in Java (conventionally). You'd be surprised how difficult it is to follow code that doesn't follow these conventions when you're used to them.
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    2. COPlease show the code for whatever class `NextState` is. We will need to see the method `get_Board()` to really know what's going on.
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    3. COI can't even understand what you're asking. Please, review your question and clearly specify the result you see and the expected one. Possibly, post a concise code sample that shows your problem and can be run
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