[]帮忙测试测试这个小程序有有关问题吗

/** * 计算字符串中子串出现的次数。 * 例如字符串abdeacdsdfsdfacddfsfdsacd中，字符串acd出现了3次 */ public class $2_SubStringNumber {        public static void main(String[] args) {        //测试A        System.out.println("测试A，0");        new $2_SubStringNumber().subStringNubmer("abc", "test");        System.out.println("测试A，1");        new $2_SubStringNumber().subStringNubmer("abc", "abc");        System.out.println("测试c，2");        new $2_SubStringNumber().subStringNubmer("abcabc", "abc");        System.out.println("测试d，2");        new $2_SubStringNumber().subStringNubmer("abcabc", "ab");    }        public int subStringNubmer(String source,String target){        int count=0;//标记字串出现的个数        int begin=0;//标记搜索的开始位        if(source.length()<target.length())return 0;        if(source.equals(target))return 1;        while(begin<=source.length()-target.length()){            if(source.substring(begin, begin+target.length()).equals(target)){                count++;            }            begin+=target.length();        }        return count;    }}

public static void main(String[] args) {        int a;        //测试A        a = new $2_SubStringNumber().subStringNubmer("abc", "test");        System.out.println("测试A，0. 结果=" + a);        a = new $2_SubStringNumber().subStringNubmer("abc", "abc");        System.out.println("测试A，1. 结果=" + a);        a = new $2_SubStringNumber().subStringNubmer("abcabc", "abc");        System.out.println("测试c，2. 结果=" + a);        a= new $2_SubStringNumber().subStringNubmer("abcabc", "ab");        System.out.println("测试d，2. 结果=" + a);            }