Bukkit/CraftBukkit — comment on commit 81df7590c381e5df2036152c3abc7e6c94f745fe
File: src/main/java/net/minecraft/server/EntityLiving.java line 425
By nickpoorman:

Fieldmaster: Your statement is most definitely incorrect. the variable i is a primitive and is local to the setHealth method. Changing i does not change this.health unless you explicitly set this.health = i; after the if statement.