public class StringDemo {

    // egységbezárás - osztályok
    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        // TODO Java API

        //1

        String baseString = "Alma van a levesben.";

        System.out.println(baseString.replace('a', 'e'));

        //2

        char[] willBeBaseString = new char[]{
                'A', 'l', 'm', 'a', ' ', 'v', 'a', 'n', ' ', 'a', ' ',
                'l', 'e', 'v', 'e', 's', 'b', 'e', 'n', '.'};

        String IAmTheBaseString = new String (willBeBaseString);

        System.out.println(IAmTheBaseString);
        System.out.println(IAmTheBaseString.substring(2));

        //3
        int blah=0, index =baseString.indexOf('e', 0);
        while (index !=-1){
            blah++;
            index = baseString.indexOf('e', index+1);

        };

        System.out.println(blah);
    }

}