I amusing following code to generate sessionkeu
  public byte[] generateSessionKey() throws NoSuchAlgorithmException, NoSuchProviderException 
          {
    KeyGenerator kgen = KeyGenerator.getInstance("AES","BC");
    kgen.init(256);
    SecretKey key = kgen.generateKey();
    byte[] symmKey = key.getEncoded();
    return symmKey;
        }
and printing it here
  byte[] aa=encryptor.generateSessionKey();
  String s1=new String(aa);
  System.out.println(s1);
and output is
 Çɤđy3F:¦ïó‹AOÜYu•{Öç„>r?Ô–
am I doing it right ?
 
     
    