OK Well... we have a very discussed and common issue. Today, in software industry, there are, mainly, two different types of languages:
- Low level languages
- High level languages
This distinction was useful about 10 years before now, the situation, at present, is a bit different. Today we talk about business-ready applications. Business models are some particular models where programs need to meet many requirements. They are so complex and so strict that coding an application with a language like c or c++ would be very time-spending. For this reason hybrid languages where invented.
We commonly know two types of languages:
Well, today there is another one:
- Compiled/Interpreted: in one word: MANAGED.
Managed languages are languages that are compiled in order to produce another code, different from the original one, but much more complex to handle. This INTERMEDIATE LANGUAGE is then INTERPETED by a program that runs the final program.
It is the common dynamics we came knowing from Java... It is a winning approach for business-ready applications. Well, now going to your question...
Operator overloading is a matter that concerns also multiple inheritance and other advanced characteristics of low level languages. Java, as well as C#, Python and so on, is a managed language, made to be easy to write and useful for building complex applications in very few time. If we included operator overloading in Java, the language would become more complex and difficult to handle.
If you program in C++ you sure understand that operator overloading is a very very very delicate matter because it can lead to very complex situations and sometimes compiler might refuse to compile because of conflicts and so on... Introducing operator overloading is to be done carefully. IT IS POWERFUL, but we pay this power with an incredibly big load of problems to handle.
OKOK IT IS TRUE, you might tell me: "HEY, But C# uses operator overloading... What the hell are you telling me? why c# supports them and Java not?". Well, this is the answer. C#, yes, implements operator overloading, but it is not like C++. There are many operator that cannot be overloaded in c# like "new" or many others that you can overload in c++... So C# supports operator overloading, but in a much lower level than c++ or other languages that fully supports it. But this is not a good answer to the earlier question... The real answer is that C# is more complex than Java. This is a pro but also a con. It is a matter of deciding where to place the language: high level, higher level, very high level? Well, Java does not support op overloading because it wants to be fast and easy to manage and use. When introducing op overloading, a language must also carry a large amount of problems caused by this new functionality.
It is exactly like questioning: "Why does Java not support multiple inheritance?" Because it is tremendously complex to manage. Think about it... IT WOULD BE IMPOSSIBLE for a managed language to support multiple inheritance... No common class tree, no object class as a common base class for all classes, no possibility of upcasting (safely) and many problems to handle, manage, foresee, keep in count...
Java wants to be simple. Even if I believe that future implementations of this language will result in supporting op overloading, you will see that the overloading dynamics will involve a fewer set of all the possibilities you have about overloading in C++.
Many others, here, also told you that overloading is useless. Well I belong to those ones who think this is not true. Well, if you think this way (op overloading is useless), then also many other features of managed languages are useless too. Think about interfaces, classes and so on, you really do not need them. You can use abstract classes for interface implementations... Let's look at c#... so many sugar syntax, LINQ and so on, they are not really necessary, BUT THEY FASTEN YOUR WORK... Well, in managed languages everything that fasten a development process is welcome and does not imply uselessness. If you think that such features are not useful than the entire language itself would be useless and we all would come back programming complex applications in c++, ada, etc. The added value of managed languages is to be measured right on this elements.
Op overloading is a very useful feature, it could be implemented in languages like Java, and this would change the language structure and purposes, it would be a good thing but a bad thing too, just a matter of tastes. But today, Java is simpler than C# even for this reason, because Java does not supports op overloading.
I know, maybe I was a little long, but hope it helps. Bye