docs: private final void checkMagic(final DataInputStream dis)
      throws LockFile.FileSecurityException,
             LockFile.UnexpectedEndOfFileException,
             LockFile.UnexpectedFileIOException, LockFile.WrongMagicException {
  
          boolean      success = true;
          final byte[] magic   = new byte[MAGIC.length];
  
          try {
              for (int i = 0; i < MAGIC.length; i++) {
                  magic[i] = dis.readByte();
  
                  if (MAGIC[i] != magic[i]) {
                      success = false;
                  }
              }
          } catch (SecurityException ex) {
              throw new FileSecurityException(this, "checkMagic", ex);
          } catch (EOFException ex) {
              throw new UnexpectedEndOfFileException(this, "checkMagic", ex);
          } catch (IOException ex) {
              throw new UnexpectedFileIOException(this, "checkMagic", ex);
          }
  
          if (!success) {
              throw new WrongMagicException(this, "checkMagic", magic);
          }
      }