public CheckpointManager(NetworkParameters params,@Nullable InputStream inputStream) throws IOException {
  this.params=checkNotNull(params);
  if (inputStream == null)   inputStream=openStream(params);
  checkNotNull(inputStream);
  inputStream=new BufferedInputStream(inputStream);
  inputStream.mark(1);
  int first=inputStream.read();
  inputStream.reset();
  if (first == BINARY_MAGIC.charAt(0))   dataHash=readBinary(inputStream);
 else   if (first == TEXTUAL_MAGIC.charAt(0))   dataHash=readTextual(inputStream);
 else   throw new IOException("Unsupported format.");
}

public CheckpointManager ( NetworkParameters params , @ Nullable InputStream inputStream ) throws IOException { this . params = checkNotNull ( params ) ; if ( inputStream == null ) inputStream = openStream ( params ) ; checkNotNull ( inputStream ) ; inputStream = new BufferedInputStream ( inputStream ) ; inputStream . mark ( 1 ) ; int first = inputStream . read ( ) ; inputStream . reset ( ) ; if ( first == BINARY_MAGIC . charAt ( 0 ) ) dataHash = readBinary ( inputStream ) ; else if ( first == TEXTUAL_MAGIC . charAt ( 0 ) ) dataHash = readTextual ( inputStream ) ; else throw new IOException ( "Unsupported format." ) ; }
loads the checkpoints from the given stream
