Hook.java

import de.robv.android.xposed.IXposedHookLoadPackage;
import de.robv.android.xposed.XC_MethodHook;
import de.robv.android.xposed.XposedBridge;
import de.robv.android.xposed.callbacks.XC_LoadPackage.LoadPackageParam;
import static de.robv.android.xposed.XposedHelpers.findAndHookMethod;

public class JoeHackXposed implements IXposedHookLoadPackage {

    private void hackLicense(final LoadPackageParam lpparam) {
      
        findAndHookMethod("es.yohan.examples.LicenseChecker", lpparam.classLoader, 
              "isValidLicense",
              String.class,
                new XC_MethodHook() {
                    @Override
                    protected void beforeHookedMethod(MethodHookParam param) throws Throwable {
                    }
                    @Override
                    protected void afterHookedMethod(MethodHookParam param) throws Throwable {
                        param.setResult(true);
                    }
                });
    }
    
    public void handleLoadPackage(final LoadPackageParam lpparam) throws Throwable {
        XposedBridge.log("Loaded app: " + lpparam.packageName);
        if (lpparam.packageName.equals("es.yohan.examples")) {
            hackLicense(lpparam);
        }
    }
    
}