code: public void println(Object x) {
          String s = String.valueOf(x);
          synchronized (this) {
              print(s);
              newLine();
          }
      }
docs: Prints an Object and then terminate the line.  This method calls
  at first String.valueOf(x) to get the printed object's string value,
  then behaves as
  though it invokes <code>{@link #print(String)}</code> and then
  <code>{@link #println()}</code>.
  
  @param x  The <code>Object</code> to be printed.