I would like help with fixing this code so the output is right public class Main {     /*      * tree.txt should produce this tree:      * 16      * / \      * 6 Z      * / \      * A D      *      * A (1), D (5), Z (10)      *      * Codes:      * A: 00      * D: 01      * Z: 1      *      * Preorder Traversal:      * 16, 6, 1 (A), 5 (D), 10 (Z)      */   }   import java.io.BufferedReader; import java.io.FileNotFoundException; import java.io.FileReader; import java.io.IOException; import java.util.ArrayList; import java.util.Collections; import java.util.HashMap; import java.util.List; import java.util.Map;   public class Huffman {     private Tree root;     private Map characterCodes;       public Huffman() {         characterCodes = new HashMap();     }       public void buildTreeFromFile(String filePath) throws FileNotFoundException {         List nodes = new ArrayList();         populateNodesFromFile(filePath, nodes);         root = buildTreeFromNodes(nodes);           buildCharacterCodes(root, "");     }       private void populateNodesFromFile(String filePath, List nodes) throws FileNotFoundException {         try (BufferedReader reader = new BufferedReader(new FileReader(filePath))) {             String line = reader.readLine();             String[] parts = line.split(",");             char ch = parts[0].charAt(0);             int freq = Integer.parseInt(parts[1]);             nodes.add(new Tree(null, null, ch, freq));                 } catch (IOException ex) {             System.err.format("IOException: %s%n", ex);         }     }       private Tree buildTreeFromNodes(List nodes) {         while (nodes.size() > 1) {             Collections.sort(nodes);             Tree left = nodes.remove(0);             Tree right = nodes.remove(0);             Tree parent = new Tree(left, right, '\0', left.getFrequency() + right.getFrequency());             nodes.add(parent);         }         return nodes.get(0);     }       private void buildCharacterCodes(Tree tree, String code) {         if (tree == null) {             return;         }         if (tree.getLeft() == null && tree.getRight() == null) {             characterCodes.put(tree.getCharecter(), code);             return;         }         buildCharacterCodes(tree.getLeft(), code + "0");         buildCharacterCodes(tree.getRight(), code + "1");     }       public void printTree() {         if (root != null) {             root.printTree();         }     }       public String getCode(char ch) {         String code = characterCodes.get(ch);             if (code == null) {             return "";         }         return code;     }       public String encode(String value) {         StringBuilder result = new StringBuilder();         for (int i = 0; i < value.length(); i++) {             char ch = value.charAt(i);             result.append(getCode(ch));         }         return result.toString();     }       public String decode(String code) {         StringBuilder result = new StringBuilder();         Tree node = root;         for (int i = 0; i < code.length(); i++) {             char ch = code.charAt(i);             if (ch == '0') {                 node = node.getLeft();             } else {                 node = node.getRight();             }             if (node.getCharecter() != '\0') {                 result.append(node.getCharecter());                 node = root;             }         }         return result.toString();     } }   public class Tree implements Comparable {         private Tree left;     private Tree right;     private char charecter;     private int frequency;       public Tree(Tree left, Tree right, char charecter, int frequency) {         this.left = left;         this.right = right;         this.charecter = charecter;         this.frequency = frequency;     }       public Tree getLeft() {         return left;     }       public Tree getRight() {         return right;     }       public int getFrequency() {         return frequency;     }       public char getCharecter() {         return charecter;     }        public void printTree() {         _printTree(this);     }       public void _printTree(Tree n) {         if (n != null) {             System.out.print(n.toString() + ",");             _printTree(n.getLeft());             _printTree(n.getRight());         }     }       @Override     public String toString() {         return String.format("%s (%2d)", getCharecter(), getFrequency());     }       @Override     public int compareTo(Tree other) {         if (this.frequency == other.frequency) {             return Integer.compare(this.frequency, other.frequency);         }         return Character.compare(this.charecter, other.charecter);     } }