Мне тоже интересно причём тут синглтон

Он сюда не пойдёт)

Не так условие прочитал

I corrected, but mistakes increased

Show error

Return }

Show the code please, it hurts to look at

I'm sorry

String apk = "";
String url = ("com.my.newproject");

try {
android.content.pm.PackageInfo pi =
getPackageManager()getPackageInfo(url,android.content.pmPackageManager.GET_ACTIVITIES);

apk = piapplicationInfopublicSourceDir;} catch (Exception_e) {show Message(e.toString());

Intent iten = new
Intent(Intent.ACTION_SEND);
iten.setType("*/*")
iten.putExtra(Intent.EXTRA_STREAM, Url, fromFile(newjava.io.File(apk)));

startActivity(Intent.createChooser(iten, "Send APK"));

Dude, you need to learn java syntax properly first. Trying to help you like that doesn't really help you to learn to do anything.

Ты можешь нарушить это. Например, метод супертипа не кидает какой-нибудь тобой созданный unchecked exception и не задекларировал в сигнатуре/ доках. а в методе подтипа ты throw его. это плохо

Yes, I agree.
But, sololearn has not this type of coding, thats why I could not understand. Also, syntax explanation is not enough explained

Read Java Code Convention

Then don't use sololearn, use something that is actually helpful to learn java.
Seriously, each and every one of your questions so far wouldn't even exist, if you tried to learn java properly

String url = ("com.my.newproject");
Change to
String url = "com.my.newproject";

And you miss dot

Maybe this is error.

String apk = "";
String url = "com.my.newproject";

try {
android.content.pm.PackageInfo pi =
getPackageManager()    .getPackageInfo(url,android.content.pmPackageManager.GET_ACTIVITIES);

apk = piapplicationInfopublicSourceDir;  
}
catch (Exception_e) {
show Message(e.toString());
}

Intent iten = new Intent(Intent.ACTION_SEND);
iten.setType("*/*")
iten.putExtra(Intent.EXTRA_STREAM, Url, fromFile(newjava.io.File(apk)));

startActivity(Intent.createChooser(iten, "Send APK"));

You missed dote