Cannot be referenced from a static context

I have the following problem, I am trying to call InterstitialLaunch.java from MainActivity.java to display Interstitial, however, in my case it reports an error from MainActivity.java and says that 'inter_launched (android.content.Context)' cannot be referenced from a static context. What can be done about this problem and how to solve the problem, some idea, thanks.

InterstitialLaunch.java

public class InterstitialLaunch extends Activity {

    public void inter_launched(Context mContext) {
        SharedPreferences prefs = mContext.getSharedPreferences("interlaunch", 0);

        SharedPreferences.Editor editor = prefs.edit();

        // Increment launch counter
        long launch_count = prefs.getLong("launch_count", 0) + 1;
        editor.putLong("launch_count", launch_count);

        // Get date of first launch
        Long date_firstLaunch = prefs.getLong("date_firstlaunch", 0);
        if (date_firstLaunch == 0) {
            date_firstLaunch = System.currentTimeMillis();
            editor.putLong("date_firstlaunch", date_firstLaunch);
        }

        // Wait at least n days before opening
        if (launch_count >= LAUNCHES_UNTIL_PROMPT) {
            if (System.currentTimeMillis() >= date_firstLaunch +
                    (DAYS_UNTIL_PROMPT * 24 * 60 * 60 * 1000)) {
                interstitialLaunch(mContext, editor);
            }
        }

        editor.apply();
    }

    public void interstitialLaunch(final Context mContext, final SharedPreferences.Editor editor) {

        MobileAds.initialize(this, new OnInitializationCompleteListener() {
            @Override
            public void onInitializationComplete(InitializationStatus initializationStatus) {
                Map<String, AdapterStatus> statusMap = initializationStatus.getAdapterStatusMap();
                for (String adapterClass : statusMap.keySet()) {
                    AdapterStatus status = statusMap.get(adapterClass);
                    Log.d("MyApp", String.format(
                            "Adapter name: %s, Description: %s, Latency: %d",
                            adapterClass, status.getDescription(), status.getLatency()));
                }

                InterstitialAd.load(getApplicationContext(),
                        getString(R.string.interstitial_id),
                        new AdRequest.Builder().build(),
                        new InterstitialAdLoadCallback() {
                            @Override
                            public void onAdLoaded(@NonNull InterstitialAd interstitialAd) {
                                interstitialAd.show(InterstitialLaunch.this);

                            }
                        }
                );

            }
        });
    }
}

MainActivity.java

InterstitialLaunch.inter_launched(MainActivity.this);

Shows this error in MainActivity.java:

Non-static method 'inter_launched(android.content.Context)' cannot be referenced from a static context

In Java, something like ClassName.method() means invoking a static method.

Your inter_launched is not a static but a dynamic (instance) method because the method doesn't have static modifier.

If you would invoke an instance method, you must do something like instanceOfTheClass.method().

For example:

InterstitialLaunch interstitialLaunch = new InterstitialLaunch();
interstitialLaunch.inter_launched(MainActivity.this);