Efficiently “modifying” an ImmutableMap

Question

We\'re currently using Guava for its immutable collections but I was surprised to find that their maps don\'t have methods to easily create new maps with minor modifications. An

Answer 1

A bit unexpected the map of Functional Java is mutable like Guava's. The list is immutable though as I would expect.

Googling for "persistent collection java" brought up: pcollections. There are's a Map implementation.

Before actually using any other implementation I would benchmark the memory and performance characteristics against Guava. I would not be surprised if it's still better.