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POAdding to ArrayList in Java
 

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    <p>I am new in Java development and I tried this program:</p> <pre><code> List&lt;String&gt; myList = new ArrayList&lt;String&gt;(); for(int i = 0;i&lt;ProductNumber;i++) { myList.add( mProducts[i].Name); } mProducts[1].Name = "Hello"; </code></pre> <p>When I made <code>println</code> to show <strong>myList</strong> content: </p> <p><strong>Expected</strong> </p> <blockquote> <p>"A"<br> "B"<br> "C" </p> </blockquote> <p><strong>Current</strong> </p> <pre><code>&gt;"A" &gt;"Hello" &gt;"C" </code></pre> <p>Can anybody tell me what is going on?</p> <p>This is the code that I made:</p> <pre><code> public class xmlParsing { private final static String XML_FILE_NAME = "Configuration.xml"; private final static String PRODUCT_NODE = "product"; private final static String TASK_NODE = "task"; private final static String NAME_ITEM = "name"; private final static String DURATION_ITEM = "duration"; private final static String RATE_ITEM = "rate"; private static int ProductNumber = 0; private static int TaskNumber = 0; private static Product mProducts[] = new Product[Product.MAX_PRODUCT_NUMBER]; public xmlParsing() { } public void parseXML () { Product[] Products = new Product[Product.MAX_PRODUCT_NUMBER]; try { File xmlFile = new File(XML_FILE_NAME); DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance(); DocumentBuilder dBuilder = dbFactory.newDocumentBuilder(); Document doc = dBuilder.parse(xmlFile); doc.getDocumentElement().normalize(); NodeList productsNode = doc.getElementsByTagName(PRODUCT_NODE); ProductNumber = productsNode.getLength(); Product mproduct = new Product(); Task mtask = new Task(); for (int i = 0; i &lt; productsNode.getLength(); i++) { Node productNode = productsNode.item(i); if (productNode.getNodeType() == Node.ELEMENT_NODE) { Element element1 = (Element) productNode; mproduct.Name = getValue(NAME_ITEM, element1); NodeList tasksNode = element1.getElementsByTagName(TASK_NODE); TaskNumber = tasksNode.getLength(); Task[] Tasks = new Task[Task.MAX_TASKS_NUMBER]; for (int j = 0; j &lt; tasksNode.getLength(); j++) { Node taskNode = tasksNode.item(j); if (taskNode.getNodeType() == Node.ELEMENT_NODE) { Element element2 = (Element) taskNode; mtask.Name = getValue(NAME_ITEM, element2); mtask.Duration = Double.parseDouble(getValue(DURATION_ITEM, element2)); mtask.Rate = Double.parseDouble(getValue(RATE_ITEM, element2)); Tasks[j] = new Task(mtask); } } mproduct.Tasks = Tasks; Products[i] = new Product(mproduct); } } } catch (Exception ex) { ex.printStackTrace(); } mProducts = Products; } private static String getValue(String tag, Element element) { NodeList nodes = element.getElementsByTagName(tag).item(0).getChildNodes(); Node node = (Node) nodes.item(0); return node.getNodeValue(); } public static List&lt;String&gt; getProdcutNames() { String ps[] = new String[ProductNumber]; List&lt;String&gt; myList = new ArrayList&lt;String&gt;(); for(int i = 0;i&lt;ProductNumber;i++) { ps[i] = mProducts[i].Name; myList.add(new String(mProducts[i].Name)); } mProducts[2].Name = "Hello"; return myList; } public int getProductNumber() { return ProductNumber; } public int getTasktNumber() { return TaskNumber; } } public class Task { public static final int MAX_TASKS_NUMBER = 100; public String Name; public double Duration; public double Rate; public Task(){ Name = ""; Duration = 0; Rate = 0; } public Task(Task t){ Name = t.Name; Duration = t.Duration; Rate = t.Rate; } } public class Product { public static final int MAX_PRODUCT_NUMBER = 200; public String Name; public Task[] Tasks; public Product(){ Name = ""; Tasks = null; } public Product(Product p){ Name = p.Name; Tasks = p.Tasks; } } public class Production { public static void main(String[] args) { xmlParsing parser = new xmlParsing(); parser.parseXML(); for(int i=0;i&lt;parser.getProductNumber();i++) System.out.println(parser.getProdcutNames().get(i)); } } </code></pre> <p>The xml file is </p> <pre><code> &lt;product&gt; &lt;name&gt;1510&lt;/name&gt; &lt;task&gt; &lt;name&gt;DECOUPAGE PRESSE 250T&lt;/name&gt; &lt;duration&gt;1&lt;/duration&gt; &lt;rate&gt;144&lt;/rate&gt; &lt;/task&gt; &lt;task&gt; &lt;name&gt;LAMINAGE PARBOLIQUE 1&lt;/name&gt; &lt;duration&gt;0&lt;/duration&gt; &lt;rate&gt;72.1&lt;/rate&gt; &lt;/task&gt; &lt;/product&gt; &lt;product&gt; &lt;name&gt;2020&lt;/name&gt; &lt;task&gt; &lt;name&gt;DECOUPAGE PRESSE 250T&lt;/name&gt; &lt;duration&gt;1&lt;/duration&gt; &lt;rate&gt;144&lt;/rate&gt; &lt;/task&gt; &lt;task&gt; &lt;name&gt;LAMINAGE PARBOLIQUE 1&lt;/name&gt; &lt;duration&gt;0&lt;/duration&gt; &lt;rate&gt;72.1&lt;/rate&gt; &lt;/task&gt; &lt;/product&gt; </code></pre> <p>Expected : 1510 2020 Current 1510 Hello</p>
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    1. COCan't replicate your behavior. Post a code sample might help.
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    2. COI would guess that myProducts contains entries with Name values of "A", "Hello", and "C".
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    3. COAre you printing mProducts instead?
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