New to Java

Hi
iam new to java .i need help on the recursive algorithm ..I have a hashmap where value is a array list for eg:

key         value 

a            ->   b ,c,d,e,f
b           ->    i,j,k,l,m
d            ->   f,p,q
i            ->   u,w,x
v            ->  z,l
r           ->  1,2,3,4
t          ->  ma,ku,sa

input to the program is "a" i need to look whether "a" has any value if it does for each value i need to look in the hashmap and find whether is has any value ,i need to go recursively to get all the elements .

output when string "a" is
a =b,c,d,e,f
b= i,j,k,l,m
i=u,w,x
d= f,p,q
I don't need any code but any help with recursive algorithm would really help
thanks for the help