I have a java.util.HashMap object m (a return value from a call to Java code) and I'd like to get a new map with an additional key-value pair.
If m were a Clojure map, I could use:
(assoc m "key" "value")
But trying that on a HashMap gives:
java.lang.ClassCastException: java.util.HashMap cannot be cast to clojure.lang.Associative
No luck with seq either:
(assoc (seq m) "key" "value")
java.lang.ClassCastException: clojure.lang.IteratorSeq cannot be cast to clojure.lang.Associative
The only way I managed to do it was to use HashMap's own put, but that returns void so I have to explicitly return m:
(do (. m put "key" "value") m)
This is not idiomatic Clojure code, plus I'm modifying m instead of creating a new map.
How to work with a HashMap in a more Clojure-ish way?