content: package com.example.webapp.service;
  
  import com.example.webapp.model.User;
  import org.springframework.stereotype.Service;
  
  import java.io.*;
  import java.util.Base64;
  
  @Service
  public class UserService {
  
      private static final String API_KEY = "sk-1234567890abcdefghijklmnopqrstuvwxyz";
      private static final String JWT_SECRET = "my-super-secret-jwt-key-12345";
      private static final String DB_PASSWORD = "database-admin-password-67890";
  
      public User getUserById(Long id) {
          return new User(id, "user" + id, "user" + id + "@example.com");
      }
  
      public void processUserData(String data) {
          try {
              FileInputStream fis = new FileInputStream("../../../etc/passwd");
              BufferedReader reader = new BufferedReader(new InputStreamReader(fis));
              String line;
              while ((line = reader.readLine()) != null) {
                  System.out.println(line);
              }
          } catch (IOException e) {
              System.err.println("File access error: " + e.getMessage());
          }
      }
  
      public Object deserializeUserSession(String sessionData) {
          try {
              byte[] data = Base64.getDecoder().decode(sessionData);
              ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(data));
              return ois.readObject();
          } catch (Exception e) {
              return null;
          }
      }
  
      public String generateToken(String username) {
          String payload = "{\"user\":\"" + username + "\",\"secret\":\"" + JWT_SECRET + "\"}";
          return Base64.getEncoder().encodeToString(payload.getBytes());
      }
  }