So far I have it so you are running around in a box, but all of the walls are the same texture! I've loaded up other textures for the walls (I want the walls a different texture than the floor) but it seems as if its being ignored... Here's my code:

        int floorTexture = glGenTextures();
    {
        InputStream in = null;
        try {               
            in = new FileInputStream("floor.png");
            PNGDecoder decoder = new PNGDecoder(in);
            ByteBuffer buffer = BufferUtils.createByteBuffer(4 * decoder.getWidth() * decoder.getHeight());
            decoder.decode(buffer, decoder.getWidth() * 4, Format.RGBA);
            buffer.flip();
            glBindTexture(GL_TEXTURE_2D, floorTexture);
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, decoder.getWidth(), decoder.getHeight(), 0, GL_RGBA,
                    GL_UNSIGNED_BYTE, buffer);
            glBindTexture(GL_TEXTURE_2D, floorTexture);


        } catch (FileNotFoundException ex) {
            System.err.println("Failed to find the texture files.");
            ex.printStackTrace();
            Display.destroy();
            System.exit(1);
        } catch (IOException ex) {
            System.err.println("Failed to load the texture files.");
            ex.printStackTrace();
            Display.destroy();
            System.exit(1);
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    int wallTexture = glGenTextures();
    {
        InputStream in = null;
        try {               
            in = new FileInputStream("walls.png");
            PNGDecoder decoder = new PNGDecoder(in);
            ByteBuffer buffer = BufferUtils.createByteBuffer(4 * decoder.getWidth() * decoder.getHeight());
            decoder.decode(buffer, decoder.getWidth() * 4, Format.RGBA);
            buffer.flip();
            glBindTexture(GL_TEXTURE_2D, wallTexture);
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
            glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, decoder.getWidth(), decoder.getHeight(), 0, GL_RGBA,
                    GL_UNSIGNED_BYTE, buffer);
            glBindTexture(GL_TEXTURE_2D, wallTexture);


        } catch (FileNotFoundException ex) {
            System.err.println("Failed to find the texture files.");
            ex.printStackTrace();
            Display.destroy();
            System.exit(1);
        } catch (IOException ex) {
            System.err.println("Failed to load the texture files.");
            ex.printStackTrace();
            Display.destroy();
            System.exit(1);
        } finally {
            if (in != null) {
                try {
                    in.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }       
    int ceilingDisplayList = glGenLists(1);
    glNewList(ceilingDisplayList, GL_COMPILE);
    glBegin(GL_QUADS);
    glTexCoord2f(0, 0);
    glVertex3f(-gridSize, ceilingHeight, -gridSize);
    glTexCoord2f(gridSize * 10 * tileSize, 0);
    glVertex3f(gridSize, ceilingHeight, -gridSize);
    glTexCoord2f(gridSize * 10 * tileSize, gridSize * 10 * tileSize);
    glVertex3f(gridSize, ceilingHeight, gridSize);
    glTexCoord2f(0, gridSize * 10 * tileSize);
    glVertex3f(-gridSize, ceilingHeight, gridSize);
    glEnd();
    glEndList();

    int wallDisplayList = glGenLists(1);
    glNewList(wallDisplayList, GL_COMPILE);

    glBegin(GL_QUADS);

    // North wall

    glTexCoord2f(0, 0);
    glVertex3f(-gridSize, floorHeight, -gridSize);
    glTexCoord2f(0, gridSize * 10 * tileSize);
    glVertex3f(gridSize, floorHeight, -gridSize);
    glTexCoord2f(gridSize * 10 * tileSize, gridSize * 10 * tileSize);
    glVertex3f(gridSize, ceilingHeight, -gridSize);
    glTexCoord2f(gridSize * 10 * tileSize, 0);
    glVertex3f(-gridSize, ceilingHeight, -gridSize);

    // West wall

    glTexCoord2f(0, 0);
    glVertex3f(-gridSize, floorHeight, -gridSize);
    glTexCoord2f(gridSize * 10 * tileSize, 0);
    glVertex3f(-gridSize, ceilingHeight, -gridSize);
    glTexCoord2f(gridSize * 10 * tileSize, gridSize * 10 * tileSize);
    glVertex3f(-gridSize, ceilingHeight, +gridSize);
    glTexCoord2f(0, gridSize * 10 * tileSize);
    glVertex3f(-gridSize, floorHeight, +gridSize);

    // East wall

    glTexCoord2f(0, 0);
    glVertex3f(+gridSize, floorHeight, -gridSize);
    glTexCoord2f(gridSize * 10 * tileSize, 0);
    glVertex3f(+gridSize, floorHeight, +gridSize);
    glTexCoord2f(gridSize * 10 * tileSize, gridSize * 10 * tileSize);
    glVertex3f(+gridSize, ceilingHeight, +gridSize);
    glTexCoord2f(0, gridSize * 10 * tileSize);
    glVertex3f(+gridSize, ceilingHeight, -gridSize);

    // South wall

    glTexCoord2f(0, 0);
    glVertex3f(-gridSize, floorHeight, +gridSize);
    glTexCoord2f(gridSize * 10 * tileSize, 0);
    glVertex3f(-gridSize, ceilingHeight, +gridSize);
    glTexCoord2f(gridSize * 10 * tileSize, gridSize * 10 * tileSize);
    glVertex3f(+gridSize, ceilingHeight, +gridSize);
    glTexCoord2f(0, gridSize * 10 * tileSize);
    glVertex3f(+gridSize, floorHeight, +gridSize);

    glEnd();

    glEndList();

    int floorDisplayList = glGenLists(1);
    glNewList(floorDisplayList, GL_COMPILE);
    glBegin(GL_QUADS);
    glTexCoord2f(0, 0);
    glVertex3f(-gridSize, floorHeight, -gridSize);
    glTexCoord2f(0, gridSize * 10 * tileSize);
    glVertex3f(-gridSize, floorHeight, gridSize);
    glTexCoord2f(gridSize * 10 * tileSize, gridSize * 10 * tileSize);
    glVertex3f(gridSize, floorHeight, gridSize);
    glTexCoord2f(gridSize * 10 * tileSize, 0);
    glVertex3f(gridSize, floorHeight, -gridSize);
    glEnd();
    glEndList();