Java implementation code for finding the number of substrings in a string

public class Test11
{
 
    private static int counter = 0;
    /**
     * @param args
     */
    public static void main(String[] args)
    {
        String str ="sdSS**&HGJhadHCASch& ^^";
        int i = stringNumbers(str);
        System.out.println(i);
    }
     
    public static int stringNumbers(String str)
    {
        if (str.indexOf("java")==-1)
        {
            return 0;
        }
        else if(str.indexOf("java") != -1)
        {
            counter++;
            stringNumbers(str.substring(str.indexOf("java")+4));
            return counter;
        }
        return 0;
    }
}

if(str.indexOf("java") != -1)
    {
        String[] str1 = str.split("java");
        System.out.println(str1.length-1);
    }
    else
    {
        System.out.println(0);
    }