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

    String str1 = "Java8 makes Java more powerful";
    String str2 = "Java";
    char c;
    char d;
    int count=0;
    boolean match = true;
    for (int i = 0; i < str1.length(); i++) {
        c = str1.charAt(i);
        for (int j = 0; j < str2.length(); j++) {
            d = str2.charAt(j);
            if (c == d) {
                match = true;
                count++;
                if(count== str2.length()){
                    i = str1.length();
                    break;
                }
                i++;
                c = str1.charAt(i);
            } else {
                match = false;
            }   
        }
    }

    if(match == true){
        System.out.println("SubString ");
    }