Ordered String from a HashMap

[spider_pig]

I have a HashMap with String keys and Integer values.
I want to get a string with the String keys in numerical order of their String values.
eg. if I have
Orange=1 apple=4 pear =2 grapefruit=3
I want the following String
apple, pear, grapefruit, orange.
I'm not sure how to do this. Any help would be much appreciated.

[jwenting]

you can't. Map's aren't sorted.