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Alex Rivera
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So I have an empty list like so List<Node> nodes = null; and then I want to add "Node"s into it try { File file = new File("test.txt"); Scanner scanner = new Scanner(file); while (true){ String first= scanner.next(); if (first.equals("-1")){ break; } Node node1= new Node(first, first); if (nodes==null){ nodes.add(node1); } if (nodes!=null){ if(nodes.contains(node1)){ nodes.add(node1); } } So obviously doing .contains in a null list gives me an exception error, but why does doing if (nodes==null){ nodes.add(node1); } also gives me a null pointer error? It seems like empty lists are immutable. How can I still keep a List structure and still build it up from empty?
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