The easy way to do it is to create a concatenated key:

String s = hashMap.get("testkey_testkey2");

unless, of course, you need to get *all* elements associated with "testkey".
In that case, you can create a main hashmap for testkey, and then have the
elements be smaller hashmaps that contain testkey2 elements. The downside to
this approach is that it will be a memory hog, if that matters for your app.
The other downside is that you'd need testkey to be able to access any
testkey2 elements.

Or you could create a sorted hashmap on the concatenated key, and then
iterate over all "testkey" elements to get testkey2. Slower, but would
probably use less memory.

Or abandon hashmaps altogether and just binary search a sorted list of
concatenated keys. Fast, doesn't use much memory, but a lot more work and
not updateable.

   The syntax simply doesn't exist in Java. Possible solutions include:

   1) Use a getter, e.g. snc.get("testkey").set("testkey2", "testval");
   2) Write a new preprocessor language for Java, and the corresponding
preprocessor.
   3) Write a new compiler for your extension to the Java language.

   - Oliver

On Tue, 25 Oct 2005 13:57:24 -0700, "Dilton McGowan II"
<diltonm@hotmail.com> wrote, quoted or indirectly quoted someone who
said :

you could build a wrapper around HashMap that glued the keys into one
object in some way, or write your own HashMap that worked with a key
pair and XORED  the two hashCodes together.