Is it guaranteed that 2 sequential calls to secure random will give different numbers?

Using SecureRandom is there a guarantee that 2 sequential calls will not return the same number?
If this is a strict requirement from client API side, is the following loop in the code redundant or not?

Random random = SecureRandom.getInstance("SHA1PRNG");  
long value1 = (long)(r.nextDouble() * LIMIT) + 1;  
long value2 = (long)(r.nextDouble() * LIMIT);  

while(value1 == value2) {  
   value2 = (long)(r.nextDouble() * LIMIT);  
}