Thread for (my) challenges

Question

Locating my or quizzes' authors' mistakes.
edit:
Should've tested on my own, but still
[ANSWERED] {
can we write so
String s1 = "sth" +1;
Seems that int and String are incompatible.}

Answer 1

Yes, it's allowed in Java. The value of s1 will be sth1. You can check it here :

https://code.sololearn.com/cIDsUE4bu85L/?ref=app

For more details on concatenation, view this post :

https://www.sololearn.com/discuss/257539/?ref=app

Answer 2

The + operator is implemented with the StringBuilder's append method. The append method is overloaded to allow appending many different types. Therefore, you can plus float, int, char and a few others.