Is there a possibility of the string equality operator (==) being fixed?

[Anatoly Kupriyanov]

I believe the thing you are asking for is contradicting the Java language
design philosophy. Java is a very simple language, relatively low-level,
like a Pure C - everything means quite literally, no hidden stuff. The ==
is a language-level and means a very simple thing.

In other languages like C++ and C# the == could also be a user-defined
operator (a method with a special syntax) and could do unexpected things.
Hence that quirky behaviour with the object comparison as demonstrated in
the Jens email.

There are few compromises which allow to make code more readable, like
auto-boxing. Even this simple thing is introducing a havoc so you have got
confused why "1 == 1" but "200 != 200" for the Integer type.
Hence it is a good thing to keep the design as simple as possible (but not
simpler!).

If you don't like explicit (unfortunately more verbose as a consequence)
syntax of Java like Objects.equals(str1, str2), and you are after cooler
languages with more features you could look into other JVM-languages like
Scala or Kotlin which do == and other things differently.


On Tue, 31 Oct 2023 at 02:11, tzengshinfu <tzengshinfu at gmail.com> wrote:

> Thank you, Anatoly, for informing me about `IntegerCache`.
> As a developer experienced in C# and JavaScript/TypeScript, I am currently
> responsible for migrating our in-house systems from C# to Java.
> I also have the responsibility of training and sharing knowledge with
> others.
>
> I was surprised by the following result in Java:
>
> ```java
> Integer int1 = 100;
> Integer int2 = 100;
> Integer int3 = int1 + 100;
> Integer int4 = int2 + 100;
> out.println(int3 == int4); // false
> ```
>
> This is different from how it works in C#:
>
> ```C#
> Int32 int1 = 100;
> Int32 int2 = 100;
> Int32 int3 = int1 + 100;
> Int32 int4 = int2 + 100;
> Console.Write(int3 == int4); // True
> ```
>
> Now, I understand that Java's design philosophy (thanks to Brian for
> patiently explaining) leads to this behavior.
> I will make an effort to understand how this works under the hood and
> include it in my Java FAQ documentation.
> My initial thoughts and suggestions were aimed at colleagues who are also
> transitioning from other programming languages and newcomers to Java who
> bring their language experiences.
> Naturally, they might find the unexpected results in certain use cases,
> and I hope to find ways to make this learning curve smoother without
> disrupting the existing framework.
>
> Without breaking the current architecture, both Solution A (changing
> String1 == String2 to String::equals()) and Solution B (introducing a new
> string/str class to replace the String class) are unfeasible (thanks to
> Nathan for preventing "I think it's rarely used, but in reality, it's not,
> and everything breaks").
>
> Can I propose a Solution C?
>
> Solution C: Introduce the === and !== operators for value comparison
> (equivalent to Object::equals()).
>
> For example:
>
> ```java
> if (Integer4 === Integer1 + Integer2 + Integer3) {
>     // Do something...
> }
> ```
>
> Would be equivalent to:
>
> ```java
> if (Integer4.equals(Integer1 + Integer2 + Integer3)) {
>     // Do something...
> }
> ```
>
> From a visual perspective, I believe that the === and !== operators can
> reduce the chances of typos and make the code look cleaner, with fewer
> parentheses compared to using equals().
> Sometimes, symbols can convey meaning more clearly than text. This idea
> stems from my experience with Delphi, where the use of keywords like begin
> and end mixed with variable declarations and expressions made code
> difficult to read in a plain text editor, despite IDE features like
> highlighting and automatic formatting. Java's use of {} solved this issue.
> However, there are also counterexamples, such as Rust's code, where
> excessive symbols may contribute to a steep learning curve.
>
> /* GET BETTER EVERY DAY */
>
>
>

-- 
WBR, Anatoly.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mail.openjdk.org/pipermail/amber-dev/attachments/20231031/ae4679bf/attachment.htm>