Difference Between Java and C++

Java is a programming language based on C++, and both are still regularly used today. While they share many features and applications, both languages have evolved enough to result in a significant difference between Java and C++. However, not everyone knows how exactly they diverge from each other.

Read on to find the key difference between Java and C++. We’ll detail each of them so you can understand the nuances.

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Java and C++ Differences

While both Java and C++ are object-oriented programming languages and share a similar syntax, any seasoned programmer can tell you the nuanced differences.

Origins

Because Java is based on C++, it’s natural to say the latter is older. C++ was developed in 1979 by Bjarne Stroustrup. However, he was working on an extension of the even older C language at Bell Labs.

Then, James Gosling at Sun Microsystems developed Java in 1995. It went through several name changes. Finally, Java was selected due to its uniqueness and ease of pronunciation.

C++’s first stable release was in October 1985, while Java’s first release would arrive 10 years later on May 23, 1995. Nevertheless, both languages underwent several years of development.

Platform Dependency

From the get-go, Java was designed to be platform independent, while C++ was and remains platform dependent. These terms radically change the way programmers and developers implement them.

Java’s source code is converted into Java byte code, which is then translated into machine code. The first two are unintelligible to machines, making interpretation necessary. However, this allows many platforms to run the same code despite having a different operating system.

If you install the proper Java Virtual Machine (JVM) on a smartphone, Java code written on a computer will run just fine. No extra processes are necessary.

On the other hand, C++ doesn’t share these features in the slightest. If you program in C++, it’s necessary to compile the code for multiple platforms if that’s on the agenda. The code can’t be shared like Java.

Therefore, Java is highly portable and saves time. On the other hand, C++ is more time-consuming if you intend to use more than one platform.

Concept

The concept behind Java is called “write once, run anywhere.” Some people add “everywhere” to the end, which is also true. C++’s concept is “write once, compile anywhere.”

With Java, you can write the source code once and run it on any device with JVM. It doesn’t matter where you wrote the code, as long as the machine has the correct JVM version installed.

However, C++ is different. You only have to write the code once, but it must be compiled multiple times if you want to run it on more than one platform. So, for example, the code that runs on Windows won’t work on Android.

The concepts behind these two languages are related to their dependence on platforms. They’re why their creators started working on them in the first place.

Compiled vs. Interpreted

Concerning the previous topic, Java and C++ differ in this regard. Thanks to the Java byte code, you can run the language on any device with a compatible JVM installed. JVM will perform interpretation, so the machines understand Java.

As JVM is performing the reading and interpreting, the device’s operating system isn’t responsible for understanding the source code or byte code. Therefore, the machine can’t understand Java byte code by itself.

On the other hand, C++ isn’t the same way. You’re already compiling code that the device understands without requiring an interpreter. Instead, the target device’s processor will translate the program into machine code that it can execute.

To simplify it, say you’re looking for a recipe for egg-fried rice. One way to make it is by following the English-language recipe. This is how compiled languages like C++ work.

However, you can also find a Chinese recipe and ask a knowledgeable friend to translate it for you as you prepare the dish. In this case, your friend is the JVM, which is how Java and other interpreted languages work.

Memory Management

When programming, objects that aren’t used will stay unless deleted. If too many objects accumulate, the system will run out of memory. The program will then terminate as there’s insufficient memory to run it.

Java deals with memory wastage automatically. Users don’t need to write code to remove unused objects since the system does it independently without user input. The Automatic Garbage Collector will start as you load the system.

However, C++ doesn’t have any automated memory management process available. As a result, programmers must handle memory allocation and de-allocation manually. Doing so will help reduce waste and boost system performance.

Supported Features

Java can be seen as a pared-down C++ in several ways, including available features. Many are ambiguous or niche, so the Java developers removed or modified them. However, that doesn’t make C++ a bad language.

Even today, there is a significant difference between Java and C++. One is you might find yourself needing certain functions in C++ that Java lacks.

Here are some features absent from Java.

Pointers
No typedef option
The delete command doesn’t work as the Automatic Garbage Collector already deletes things for you
C++ templates are gone
No friend classes or friend functions
Multiple inheritances are replaced with multi-level inheritance
No operator overloading
No inline functions
In addition, there are:
No preprocessors
No macros
No global variables or functions
Unsigned int option is absent

Virtual Keywords

In C++, you can use virtual keywords to make virtual functions. The latter works as the parent class function to redefine a child class. To make a function behave this way, you’ll need to enter the keyword “virtual.”

The keyword will make the compiler perform either late binding or dynamic linkage.

Virtual functions can achieve runtime polymorphism, and if a class is derived from a different one with a virtual function, the function definition in the derived class is redefinable.

Java has virtual functions too, but it doesn’t have virtual keywords. Therefore, you’ll need to write them using different techniques.

Thread Support

Multithreading refers to the act of dividing programs into more than two parts that run simultaneously. Programmers can assign different tasks to each thread, so the available resources aren’t wasted. Computers with more than one CPU will make multithreading more effective.

Because each thread runs parallel to others independently, an exception on one usually won’t affect the others. The computer’s operating system will also divide processing time among the threads. As a result, compared to single-thread programs, multi-threaded programs run faster and use resources more efficiently.

From the beginning, Java was designed as a multi-threaded programming language. Due to this implementation, you don’t need to rely on third-party libraries to create threads.

However, C++ is different. Before C++ 11, the language had no built-in multithreading support. So it relied on the operating system for this function instead.

While C++ 11 has this support, you must download and install third-party programs like POSIX to perform multithreading.

Compatibility With Other Programming Languages

Java derives much of its syntax and other features from C and C++. However, it’s not backward compatible with any of the languages that influenced it, which is a difference between Java and C++. Therefore, it won’t work with others like Ada 83 and Pascal.

Though C++ isn’t 100% backward compatible with the languages that influenced it, the feature does exist for the language.

Libraries

Libraries are a collection of classes created by other users. You can run the classes in your code when you download them. They help expand your programming language’s capabilities and allow you to use proven code instead of blindly writing your own, which can take a lot of time.

Java libraries are a dime a dozen, meaning you can find them online and use them for free. They also support code reusability and are diverse.

Java will only let calls through the Java Native Interface through, though Java Native Access has been added later in the language’s life.

While C++ does have libraries, they tend to be low-level functionality examples. Code reusability isn’t high on this language’s priority. Where C++ differs is that direct calls to the native system libraries are permitted.

Usage

Because Java is great for high-level applications, you can find it in the following uses:

Android and Google OS apps
Internet of Things devices such as smartphones, tablets, and some industrial equipment
Cloud apps
Chatbot code
Secure and scalable web applications
Some games for PC and Android
Machine learning and other scientific applications
Enterprise programs like data storage and customer management apps
Despite Java being simpler, C++ isn’t going away either. You can find it employed in these areas:
Operating systems like Windows and iOS
Game development tools
Video game engines
Internet of Things devices
Web browsers
Flight software
Google Search
Special effects on movies and TV shows
Medical machines