Utilizing immutability is considered to have many desired benefits when it comes to software development and reasoning about programs. It is also one of the core principles of functional programming, and many programming languages have support for specifying immutability. Developers can by specifying immutability write code that, for example, prevent program state from being unintentionally mut...

One of the main reasons aliasing has to be controlled, as highlighted in another chapter [1] of this book [2], is the possibility that a variable can unexpectedly change its value without the referrer’s knowledge. This book will not be complete without a discussion of the impact of immutability on referenceabundant imperative object-oriented languages. In this chapter we briefly survey possible...

Functional programming typically emphasizes programmingwith first-class functions and immutable data. Immutable data types enable fault tolerance in distributed systems, and ensure process isolation in message-passing concurrency, among other applications. However, beyond the distinction between reassignable and non-reassignable fields, Scala’s type system does not have a built-in notion of imm...

Immutability is a very useful and desirable property for objects. This paper investigates different possible notions of immutability for Java objects, to find out which notion is the most intuitive and useful, both when it comes to ways of enforcing immutability of objects, and when it comes to exploiting information about (im)mutability of objects in program verification and in various static ...

We extend a Java-like language with immutability specifications and a static type system for verifying immutability. A class modifier immutable specifies that all class instances are immutable objects. Ownership types specify the depth of object states and enforce encapsulation of representation objects. The type system guarantees that the state of immutable objects does not visibly mutate duri...

Multiple ownership [4] introduced a novel approach to managing object ownership information called “owners-as-boxes”. Each object is placed in a “box” or context and the nesting relationship between “boxes” or contexts respects the object accesses that happen during the program’s execution. No restrictions are placed on which objects are allowed to access which other objects, rather the ownersh...

Reference immutability enforces the property that a reference cannot be used to mutate the referenced object. There are several type-based formulations for reference immutability in the literature. However, we are not aware of a dataflow formulation. In this paper, we present a dataflow formulation for reference immutability using CFL-reachability, as well as a type-based formulation using view...

Object immutability is a familiar concept that allows safe sharing of objects. Existing language support for immutability is based on immutable classes. However, class-based approaches are restrictive because programmers can neither make instances of arbitrary classes immutable, nor can they control when an instance becomes immutable. These restrictions prevent many interesting applications whe...