Java - Write code to search a char inside a string

Requirements

Write code to search a char inside a string

Demo

//package com.book2s;

public class Main {
    public static void main(String[] argv) {
        String str = "book2s.com";
        char ch = 'a';
        System.out.println(contains(str, ch));
    }//ww  w .j a v a  2s.co  m

    public static boolean contains(final String str, final char ch) {
        if (isEmpty(str)) {
            return false;
        }
        return str.indexOf(ch) >= 0;
    }

    public static boolean contains(final String s1, final String s2) {
        if (isEmpty(s1)) {
            return false;
        }
        return s1.indexOf(s2) >= 0;
    }

    public static final boolean isEmpty(final String text) {
        return text == null || text.length() == 0;
    }
}