Java code to generate unique random key

 import java.util.Random;  
 public class RandomKeyGenerator {  
    public static String generateRandomKey() {   
 String allChars = “abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890!@$%^*()_”;   
     Random random = new Random();   
     int length = random.nextInt(5);   
     length+=7;  
     char[] chars = new char[length];   
     for (int i=0; i      chars[i] = allChars.charAt(random.nextInt(allChars.length()));   
      }   
     return new String(chars);   
   }   
 }