Java – Should I keep tokens safely in memory or sqlite? Or please suggest

I

started learning Android a few days ago, and so far I’ve completed the implementation of the login activity, with the main activity extending the abstract base activity.

Clicking on a navigation bar item opens the xml from Fragments.

I

have a question about the token I received after a successful login. This token is used with each request to get data after a successful login. Should I keep the token safely in the sqlite database, or should I create a public property in the main activity? The Main Activity will always remain in memory because this will open the fragment.

I can suggest 3 options:
1) You can save the token to a file as follows:

public static void saveToken(Context ctx, String fileName, Object token) {
        if (token == null) {
            ctx.deleteFile(fileName);
        } else {
            ObjectOutputStream out = null;
            try {
                FileOutputStream fout = ctx.openFileOutput(fileName, 0);
                out = new ObjectOutputStream(fout);
                out.writeObject(token);
                fout.getFD().sync();
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                try {
                    if (out != null)
                        out.close();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
    }

Ensure that the object token implements the java.io.Serializable interface.

Usage prior to API level 24:

saveToken(appContext, someFileName, someTokenObject);

API level 24 and higher usage:

saveToken(appContext.createDeviceProtectedStorageContext(), someFileName, someTokenObject);

2) Encrypt the database using the SQLCipher library.

3) You can encrypt your token using the keystore system https://developer.android.com/training/articles/keystore.html