Best practice for static references in libgdx project?

Question

My libGDX / box2d project is targeting Android, iOS and Desktop as a platform. I have read somewhere that it is not good to use a static Texture Atlas, because it might be removed from the memory, once the app is in background. Therefore I am passing the same Texture Atlas as parameter to my controller classes, but I still have many static variables (constants) for all kinds of purposes. I use them for paths, regions, box2d, music, user data, ... Isn't there a probability that these variables will be removed too, when the app is in background? Should I change that? How would I approach that?

public static final String ATLAS_PATH = "atlas/myAtlas.atlas";
public static final String ATLAS_REGION_OFF = "off";
public static final String SFX_KEY_AIRHORN = "airhorn";
public static final short BIT_GROUND = 0x0001;
public static final String USER_DATA_HEAD = "head";
public static final short ID_AND_RENDER_ORDER_PLAYER = 1;