Do some light reformatting

Author: stevenlagoy

src/main/java/core/FileOperations.java

@@ -1,9 +1,11 @@
 package core;
 
 import java.io.File;
+import java.io.FileOutputStream;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStreamWriter;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.DirectoryStream;
 import java.nio.file.Files;
@@ -79,10 +81,14 @@ public static Set<Path> listFiles(Path dir) throws IOException {
      *             If the directory path is invalid or unable to be located.
      */
     public static Set<Path> listFiles(Path dir, FileExtension extension) throws IOException {
+        if (dir == null) {
+            throw new IllegalArgumentException("Path cannot be null");
+        }
         Set<Path> pathSet = new HashSet<>();
         dir = dir.normalize();
-        if (!Files.exists(dir))
+        if (!Files.exists(dir)) {
             throw new IOException("The specified path, " + dir.toString() + ", was not found.");
+        }
         try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir)) {
             for (Path path : stream) {
                 String fileName = path.getFileName().toString();
@@ -140,8 +146,10 @@ public static void writeFile(String filename, String extension, Path destination
     public static void writeFile(File file, List<String> content) {
         try {
             Files.createDirectories(file.getParentFile().toPath());
-            file.createNewFile();
-            try (FileWriter writer = new FileWriter(file, false)) {
+            if (!file.createNewFile() && !file.exists()) {
+                throw new IOException("Failed to create new file: " + file.getAbsolutePath());
+            }
+            try (OutputStreamWriter writer = new OutputStreamWriter(new FileOutputStream(file, false), StandardCharsets.UTF_8)) {
                 for (String line : content) {
                     writer.write(line + "\n");
                 }

src/main/java/core/JSONObject.java

@@ -305,6 +305,7 @@ public Iterator<Object> iterator() {
      *
      * @see JSONObject#toString(int)
      */
+    @Override
     public String toString() {
         return toString(0);
     }
@@ -349,7 +350,12 @@ else if (value instanceof List<?>) {
                     if (item == null) {
                         System.out.println("null");
                     }
-                    sb.append(item.toString(indent + 1));
+                    if (item != null) {
+                        sb.append(item.toString(indent + 1));
+                    }
+                    else {
+                        sb.append("null");
+                    }
                     if (i < list.size() - 1)
                         sb.append(",");
                     sb.append("\n");
@@ -450,6 +456,11 @@ else if (o instanceof List<?>)
         return entries;
     }
 
+    @Override
+    public int hashCode() {
+        return this.toString().hashCode();
+    }
+
     /**
      * Determine whether this JSONObect is equal to the other JSONObject by comparing their String representations.
      *