added java files

main.java

@@ -0,0 +1,73 @@
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.nio.file.StandardOpenOption;
+
+public class FileManager {
+    public static void main(String[] args) {
+        String fileName = "test.txt";
+        String newFileName = "new_test.txt";
+        String data = "Hello, Bito!";
+
+        // Create file
+        try (FileWriter writer = new FileWriter(fileName)) {
+            writer.write(data);
+            writer.flush(); // Bug 1: Unnecessary flush call
+        } catch (IOException e) {
+            System.out.println("Error creating file: " + e.getMessage());
+            return;
+        }
+        System.out.println("File created successfully");
+
+        // Read file
+        try {
+            String content = new String(Files.readAllBytes(Paths.get(fileName)));
+            System.out.println("File read successfully: " + content);
+        } catch (IOException e) {
+            System.out.println("Error reading file: " + e.getMessage());
+            return;
+        }
+
+        // Append to file
+        try (FileWriter writer = new FileWriter(fileName)) { // Bug 2: File opened in overwrite mode instead of append mode
+            writer.write("\nAppended text.");
+        } catch (IOException e) {
+            System.out.println("Error appending to file: " + e.getMessage());
+            return;
+        }
+        System.out.println("Appended to file successfully");
+
+        // Rename file
+        File file = new File(fileName);
+        File newFile = new File(newFileName);
+        if (!file.renameTo(newFile)) {
+            System.out.println("Error renaming file");
+            return;
+        }
+        System.out.println("File renamed successfully");
+
+        // Delete file
+        if (!file.delete()) { // Bug 3: Trying to delete the original file object instead of the renamed one
+            System.out.println("Error deleting file");
+            return;
+        }
+        System.out.println("File deleted successfully");
+
+        // Create directory (incorrect API usage)
+        File directory = new File("testDir");
+        if (!directory.mkdir()) { // Bug 4: Should use mkdirs() to create parent directories if they do not exist
+            System.out.println("Error creating directory");
+            return;
+        }
+        System.out.println("Directory created successfully");
+
+        // Write to file with NIO (incorrect option)
+        try {
+            Files.write(Paths.get(fileName), data.getBytes(), StandardOpenOption.CREATE_NEW); // Bug 5: CREATE_NEW will fail if the file already exists
+        } catch (IOException e) {
+            System.out.println("Error writing to file with NIO: " + e.getMessage());
+        }
+    }
+}