How to generate unique random sequence of four numbers in java

i've been trying to figure out how to write the code in Java that would generate unique number sequences as follows:**

0012 3929 2003 2201 3994 etc...

55562 23369 66665 77742 15489 etc...

556612 211135 222566 333365 etc...

with all possible numbers in sequence of four or five or more number blocks...