NullPointerException when if-branch contains multiple statements

Consider the following code snippet:

(if true ((println "Hello") (println "World")) )

This will print the following:

Hello
World
NullPointerException   user/eval769 (NO_SOURCE_FILE:1)

The reason is (as described e.g. here), that the return value of (println "Hello") -- which is nil -- will be called as a function, with the return value of the second argument.
This can be prevented by using do:

(if true (do (println "Hello") (println "World")) )

Result:

Hello
World
nil