public void putChar(int column, int row, char ch, Attributes attributes) {
    if (column >= 0 && column < columns && row >= 0 && row < rows) {
      buffer[column][row].setAttributes(attributes);
      buffer[column][row].setChar(ch);
    }
  }
Represents a buffer of the terminal screen for double-buffering.
hbase-hbtop/src/main/java/org/apache/hadoop/hbase/hbtop/terminal/impl/ScreenBuffer.java