How to know if a given string is substring from another string in Java

Question

Hi I have to compute if a given string is substring of a bigger string. For example

String str = \"Hallo my world\";
String substr = \"my\"

<

Answer 1

public static boolean isSubstring(String s1, String s2){
    if(s1.length()

This checks if s2 is a substring of s1.