public Cube() {
    faces = new Shape3D[6]; //yes there are more faces than just this one, but they're all the same, aside from vertices
    QuadArray qa1 = new QuadArray(4, QuadArray.COORDINATES | QuadArray.TEXTURE_COORDINATE_2);
    qa1.setCapability(QuadArray.ALLOW_TEXCOORD_READ);
    qa1.setCapability(QuadArray.ALLOW_TEXCOORD_WRITE);
    float[] coordinates1 = {-0.5f,-0.5f,-0.5f, 0.5f,-0.5f,-0.5f, 0.5f,-0.5f,0.5f, -0.5f,-0.5f,0.5f}; //bottom face
    qa1.setCoordinates(0, coordinates1);
    applyTextureCoords(qa1); //apply our coordinates
    faces[0] = new Shape3D(qa1);
    ...
}

//...
public void applyTextureCoords(QuadArray array) {
        float[] textureCoordinates = {0.0f,0.0f, 1.0f,0.0f, 1.0f,1.0f, 0.0f,1.0f}; //all of them are going to be the same
}