code: public double getValueDouble() throws NullPointerException {
  		if (current == State.VALUE_DOUBLE) {
  			return valueDouble;
  		} else if (current == State.VALUE_NULL) {
  			return -1;
  		} else if (current == State.VALUE_LONG) {
  			return valueLong;
  		} else {
  			throw new IllegalStateException("unexpected state. state=" + current);
  		}
  	}
docs: Get the current value as double-precison floating point number.<br>
  
  <p>
  Please call if {@link JsonPullParser#getEventType()} returns {@link State#VALUE_DOUBLE}.
  </p>
  
  @return The current value read as double-precison floating point number.
  @throws NullPointerException The current value is null ({@link #getEventType()} returns {@link State#VALUE_NULL}.)