サンプルだからでしょ>>442
JDKのソース読んだことある？

public abstract class ColorModel implements Transparency{
  private long pData; // Placeholder for data for native functions

  /**
   * The total number of bits in the pixel.
   */
  protected int pixel_bits;
  int nBits[];
  int transparency = Transparency.TRANSLUCENT;
  boolean supportsAlpha = true;
  boolean isAlphaPremultiplied = false;
  int numComponents = -1;
  int numColorComponents = -1;
  ColorSpace colorSpace = ColorSpace.getInstance(ColorSpace.CS_sRGB);
  int colorSpaceType = ColorSpace.TYPE_RGB;
  int maxBits;
  boolean is_sRGB = true;