where does truelicense persist the license file

Question

This question is very specific to the implementation of TrueLicense and its workings. With the help of the tutorials here and the more helpful here, I have successfully been able to apply licensing on my software using TrueLicense. However, I am still not clear on certain aspects of TrueLicense and how it works, and am hoping somebody can enlighten me. For now, what I don't understand is that when I call the

licenseManager.install() 

method (making sure the rest of the prerequisites are fulfilled) where is the license file actually getting persisted. I know that it is getting persisted somehow because the second time I start the application and run the

licenseManager.verify() 

method it returns happy. I would really appreciate some insight on this.

Answer 1

From the source-code (TrueLicense):

/**
 * Installs the given license key as the current license key.
 * If {@code key} is {@code null}, the current license key gets
 * uninstalled (but the cached license certificate is not cleared).
 */
protected synchronized void setLicenseKey(final byte[] key) {
    final Preferences prefs = getLicenseParam().getPreferences();
    if (null != key)
        prefs.putByteArray(PREFERENCES_KEY, key);
    else
        prefs.remove(PREFERENCES_KEY);
}

If you use the standard Java preferences API (java.util.prefs.Preferences), you will see this in the registry on Windows. On Linux and OS X, there is a hidden "." directory that has these keys.

Typically, I just use the userNodeForPackage method, since it does not require an admin on Windows.