Immutable array in Java
To create an "immutable array" in Java, domesticate an array with a List and make it cozy within a Collections.unmodifiableList()
:
This constructs a read-only List habitat, putting a stopper on structural modifications. However, the contained objects can still run wild, if they are mutable.
Also, Java 9 says "present"
For those at the Java 9 house-party or later, we have party tricks like List.of
and similar flicks from Set
and Map
interfaces for generating immutable collections:
Deep Dive: Introduction&Possible hiring
Unmodifiable vs Immutable: long-lost twins separated at birth
It's essential to distinguish between unmodifiable and immutable. Unmodifiable list is the party bouncer stopping uninvited guests, whereas immutable implies the location and guest-list remain as is. Zilch change!
Defensive copying: Copycats aren't always bad
When aiming for undisputed immutability, copy the original array like a pro con-artist. This defensive copy prevents unsolicited changes:
Secret Libraries: The Restricted Section
Step into the utility libraries like Guava's ImmutableList or Apache Commons Lang ImmutablePair for making arrays immutable. They are the Hogwarts of immutable arrays.
Performance considerations: Speed vs Integrity
Cloning arrays is like photocopying documents - useful but resource-consuming. Especially when dealing with large arrays, consider reusing immutable empty arrays or invent lazy copying mechanisms.
Advanced patterns: The skeleton key
Final does not mean final
Declaring an array final
is akin to driving on the highway and never stopping. It keeps you going, but it doesn't stop you from changing lanes (element modification).
Immutable objects: The Untouchables
Immutable objects are like that antique vase your grandma has. Once made, they can't be changed. Just look and admire (and avoid breaking them).
Trust issues with client code
Expose an array to external clients and you are in for a wild ride. If arrays are not rock-solid immutable, your clients might still modify elements. Prepare for the unexpected.
The New Kid on the block: Java 9's Immutable Collections
Java 9 brings the Immutable Collections API which helps you create immutable collections. It's like a shortcut to your favorite cafe. Why go the long way when you can save so much time?
Less memory to lose
Reuse to refuse memory wastage
To save your precious memory, reuse immutable empty arrays:
Immutable vs The World
List.of vs Collections.unmodifiableList
While List.of
prevents structural changes and stops you from replacing elements, Collections.unmodifiableList
only signs up for the former.
Immutable collections: Our superheroes
Using immutable collections is like a taste test. It might seem bland initially, but it's a flavor enhancer down the road. Embrace the exquisite taste of data integrity and predictable behavior in your application.
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