Please explain the << in this code ???

int w = 100;
int h = 100;
int pix[] = new int[w * h];
int index = 0;
for (int y = 0; y &lt; h; y++) {
int red = (y * 255) / (h - 1);
for (int x = 0; x &lt; w; x++) {
int blue = (x * 255) / (w - 1);
pix[index++] = (255 &lt;&lt; 24) | (red &lt;&lt; 16) | blue;
}
}
Image img = createImage(new MemoryImageSource(w, h, pix, 0, w));