OUTPUT: http://i.imgur.com/jv5xR.png

import org.lwjgl.opengl.GL11;
import org.newdawn.slick.opengl.Texture;

abstract class Block {
    private Texture texture;

    protected int x;
    protected int y;

    protected BlockType type;

    private static int blockWidth = 25;
    private static int blockHeight = 25;

    public void setTexture(Texture tex) {
        this.texture = tex;
    }

    public void draw() {
        texture.bind();

        int realX = x * blockWidth;
        int realY = y * blockHeight;

        int textureW = blockWidth;
        int textureH = blockHeight;

        GL11.glBegin(GL11.GL_QUADS);
            GL11.glTexCoord2f(0, 0);
            GL11.glVertex2f(realX, realY);

            GL11.glTexCoord2f(1, 0);
            GL11.glVertex2f(realX + textureW, realY);

            GL11.glTexCoord2f(1, 1);
            GL11.glVertex2f(realX + textureW, realY + textureH);

            GL11.glTexCoord2f(0, 1);
            GL11.glVertex2f(realX, realY + textureH);
        GL11.glEnd();
    }

}