Step 1:  Fill the 3 litre jar first and then transfer it to the 5 litre jar
Step 2:  then again fill the 3 litre jar and fill the remaining 5 litre jar(now 5 l jar is completely filled and you are left with 1 litre in 3 l jar)
Step 3:empty the 5 l jar and transfer 1 litre from 3l to 5l jar.
Step 4:fill the 3 litre jar again and transfer it to the 5 litre jar making it 4.

5      3
________
0       0
0       3
3       3
5       1
1        3
4        0