java唯一的字符串生成器

public class UniqueStringGenerator {     private UniqueStringGenerator()     {     }     public static synchronized String getUniqueString()     {         if(generateCount > 99999)             generateCount = 0;         String uniqueNumber = Long.toString(System.currentTimeMillis()) + Integer.toString(generateCount);         generateCount++;         return uniqueNumber;     }     private static final int MAX_GENERATE_COUNT = 99999;     private static int generateCount = 0; }