title: When I write more than one object I get this IO error "invalid type code: AC" why?
body: <p>This is my file handling class....i dont have any errors in any other classes ...the program is also overwring the data in the file..it is not appending   </p>
  
  <pre><code>import java.io.FileOutputStream;
  import java.io.FileInputStream;
  import java.io.IOException;
  import java.io.ObjectOutputStream;
  import java.io.ObjectInputStream;
  import java.io.EOFException;
  import java.lang.ClassNotFoundException;
  import java.util.NoSuchElementException;
  
  public class FileHandling {
  
      FileHandling() {
      }
  
      public void addCustomer(Customer customerObject, String filePath) {
  
          ObjectOutputStream output;
  
          try {
              FileOutputStream fileOut = new FileOutputStream(filePath, true);
              output = new ObjectOutputStream(fileOut);
              output.writeObject(customerObject);
              output.close();
          }
  
          catch (IOException ioexception) {
              System.err.println("Error with file");
          }
      // end addCustomer function
      }
  
      public void retrieveCustomerData(String filePath) {
  
          Customer record = new Customer();
  
          ObjectInputStream input;
  
          try {
              FileInputStream fileOut = new FileInputStream(filePath);
              input = new ObjectInputStream(fileOut);
  
          }
  
          catch (IOException ioexception) {
              System.err.println("Error with file1");
              return;
          }
  
          try {
              while (true &amp;&amp; input != null) {
  
                  record = (Customer) input.readObject();
  
                  System.out.println(record.getFirstName());
                  System.out.println(record.getLastName());
                  System.out.println(record.getEmailAddress());
  
              // end while loop   
              }
  
          // end try block    
          } catch (EOFException endOfFileException) {
  
          }
  
          catch (ClassNotFoundException ioexception) {
              System.err.println("Class not Found");
          }
  
          catch (IOException ioexception) {
              System.err.println("Error with file2");
              System.err.println(ioexception.getMessage());
          }
  
          try {
              if (input != null)
                  input.close();
          }
  
          catch (IOException ioException) {
              System.err.println("Error closing file");
          }
      // end retrieveCustomerData function
      }
  
  // end class fileHandling
  }
  </code></pre>