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C# vs Java: 31 Important Differences you should Know

C# vs Java


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C# and Java are two of the leading programming languages in the world to learn and earn. Both of them are high-level programming languages sharing several similarities, including an object-oriented approach of programming and having a being highly influenced by C++.

While Java is a language considered to be among the best options for client-side web applications, C# leads the application development for the Microsoft ecosystem from the front.

There are a galore of differences between the two general-purpose programming languages that we will explore shortly. But before that, let’s get a brief introduction of C# and Java.

Java – The Popular Programming Language of the Web

Developed by James Gosling at Sun Microsystems, Java made its debut appearance in the May of 1995. The general-purpose programming language is concurrent, class-based, and object-oriented. It is specifically designed to have fewer implementation dependencies.

Java works on the mantra of WORA (Write Once, Run Anywhere). This simply means that the compiled Java code (bytecode) is able to run on different platforms that provide support for Java without the need for recompilation.

Java is heavily inspired by C++. As a result, much of its syntax is derived from C++. The latest version of Java, which is Java 11 and also an LTS (Long-Term Support) version, was released on 25th September 2018.

C# – The Programming Language of the Microsoft Ecosystem

Designed by Anders Hejlsberg, C# saw the light of the day sometime in 2000. C# is an imperative, multi-paradigm, object-oriented, general-purpose programming language. It is one of the programming languages designed for the Common Language Infrastructure.

The high-level programming language was developed by Microsoft within its .NET initiative. Later, it was approved as a standard by ECMA and ISO. The latest version of C# is 7.3, released in 2018.

C# vs Java: The Battle Begins

  • Application Development

The Java programming language is typically used for developing complex web-based, highly concurrent applications in an open-source ecosystem. C#, on the other hand, is used for game, mobile, and web application development specifically for Microsoft platforms.

While Java is a great choice for building messaging applications, C# has a better ability for developing virtual reality projects. The programming language is specifically powerful for building Windows-based desktop applications and games.

There are a number of tools available for allowing applications written in C# to be used over mobile and desktop belonging to different non-Microsoft-based operating systems.

  • Arrays

Both C# and Java support arrays. However, the way each of the programming languages uses them is different. While arrays in Java are a direct specialization of the object, arrays in C# are a specialization of the system.

Also, Java provides support for only jagged arrays (also known as an array of arrays). C#, on the other hand, supports jagged arrays as well as multi-dimensional arrays.

  • Class Properties

Unlike Java, C# has something called class properties. In order to offer a flexible mechanism for some class to expose private fields, the class property is used. It is a member of the class.

Though Java doesn’t provide support for properties, it can be implemented by defining a pair of accessor and mutator methods.

  • Closure Functionality

Though both C# and Java offer anonymous methods, only the former offers anonymous methods providing closure functionality.

  • Code Execution

The Java programming language is designed to run on any Java platform with the assistance of JRE (Java Runtime Environment).  In Java, the written source code is first compiled into bytecode. It is then converted into machine code that is ready to be executed on any JRE.

The C# programming language, on the other side, is designed to execute on CLR (Common Language Runtime).

The source code in C# is interpreted into bytecode, known as MSIL (Microsoft Intermediate Language), which is then compiled by CLR. The JIT compiler converts the MSIL into native machine code thereafter.

  • Community, Resources, and Standardization

Compared to Java, C# resources are very limited. The C# libraries work only within the Microsoft ecosystem. On the other hand, the Java library and resource ecosystem are humongous in addition to being well-documented.

Java is backed by a huge community that provides not only free-to-use libraries but ones that are open-source too. Hence, they can be modified and tweaked as per the requirements. Contrarily, free libraries from the Microsoft community is a downer for C#.

Even though Java is a proprietary product of Oracle, the Java API is primarily controlled and managed via an open community process. On the other hand, the C# API is completely controlled by Microsoft and the C# is defined by ECMA and ISO standards.

  • Conditional Compilation

C# allows using conditional compilation by means of preprocessor directives. However, there is no conditional compilation possible in Java. The feature allows defining methods that are compiled when specific symbols are defined.

Typically, conditional compilation is used with methods that are used solely for debug builds of a software or application. Conditional compilation can be used for automatically removing the code for release builds if the code is useful only during the debugging process.

  • Delegates

Java doesn’t have delegates while C# has them. Delegates are type-safe method pointers that are used for implementing event handling.

The debate about delegates being good or bad is open. Some argue that the use of delegates complicates the method invocation model. This is because they are handled via something called reflection, which is a slow process.

Those in favor of delegates stress that using delegates can simplify the code by means of eliminating the need to declare new classes, which are solely created to hook to events.

  • Enumerations

The C# programming languages provide support for enumerations, which are type-safe value types. These are limited to a defined set of constant variables and structures that are user-defined value types.

Though Java doesn’t have support for enumerations, it is possible to specify a class for emulating them.

Note: – C# supports much more fundamental data types as well as allows more extension to the value types than Java.

  • Exception Handling

Although exception handling is available in both the programming languages, the treatment the feature receives is different. Java offers a clear distinction between checked and unchecked exceptions, hence supports both.

In C#, on the contrary, there is no provision for checked exceptions and only unchecked exceptions are available. However, unlike Java, C# supports the functionality to catch arithmetic exceptions.

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  • Explicit Member Implementation

C# has something called explicit member implementation, while Java doesn’t. The feature allows a class to implement methods of an interface other than the class methods. It also allows for implementing two distinct interfaces that have a method of the same name.

  • Generics

In Java, the generics feature is compiler-assisted and implemented by using erasures. Upon the Java code successfully compiled to bytecode, information about generic types is lost. C#, alternatively, has a better provision for the generics feature.

In C#, generics are integrated into the CLI. Hence, the information about generics is preserved even after compilation. Moreover, the programming language allows the type information to be available at runtime.

  • Goto Statement

In order to transfer the program control directly to a labeled statement, the goto statement is used. While Java doesn’t have any provision for using the goto statement, C# provides support for the same.

Although the typical use of a goto statement is for transferring control to a specific switch-case label (or the default label in a switch statement), it can also be used in some scenarios for exiting from deeply nested loops.

  • IDEs and Text Editors

Compared to C#, Java has a gigantic arsenal of tools. #develop, MonoDevelop, and Visual Studio are the most-preferred IDEs for C#. Eclipse, IntelliJ IDEA, and NetBeans are the big three of Java IDEs along with several other great IDEs and numerous text editors to choose from.

  • Inbuilt Data Types Passed by Value

In the Java programming language, the built-in data types that are passed by value are named primitive types. On the other hand, simple types are the label given to inbuilt data types that are passed by value in C#.

  • Iterator

While C# has the IEnumerator, Java has Iterator for the same purpose. However, there are several dissimilarities between the two, described as follows:

  • Iterator has the remove method for removing elements from the underlying collection. IEnumerator has no equivalent of it
  • Iterator has the hasNext method, while IEnumerator has MoveNext method for verifying the result
  • The function of Iterator’s next method is replicated by IEnumerator’s MoveNext method
  • While Iterator’s next method returns the next element in the collection, IEnumerator necessitates for using the Current property after calling the MoveNext method
  • Managed and Unmanaged Code

There are several errors that are exclusive to the C# programming language. This is due to its support for both managed and unmanaged code. Java only supports pure managed code. However, C#’s support of both types of code allows it to interface the same with existing code.

  • Methods by Default

A virtual method guarantees that the most overridden method of an object is called. All methods in Java are virtual by default, while C# has methods that are non-virtual by default.

  • Namespaces

Though both C# and Java have namespaces, the namespace in C# doesn’t specify the location of the source file. Also, the C# programming language features creating aliases for long namespaces.

The feature also offers a workaround for preventing namespace clashes in the code when identical types are imported into the code base. In order to use aliases for a namespace, the using keyword is used.

An alias namespace belongs to the scope of the namespace it is declared in. Upon code compilation, the alias is put in effect by the generation of a token for the fully qualified name.

  • Operator Overloading

Operator overloading is a feature that allows redefining the operation of an operator for user-defined data types. Java’s design philosophy stresses that the abuse of operator overloading can result in code that is harder to understand as well as difficult to debug.

Therefore, operator overloading is absent in the Java programming language. The lack of feature somewhat makes Java unsuitable for developing mathematics-based programs.

Nonetheless, operator overloading is available in C# because its design philosophy supports the idea that when used prudently, the feature can make the code more readable and succinct.

  • Output Parameters

Java doesn’t have support for output parameters. C#, contrarily, supports the feature. It assists in returning multiple values.

  • Paradigm

Java is a class-based, object-oriented language derived from C++. The high-level, robust, secured, general-purpose programming language is developed by Oracle.

C# is an object-oriented, component-oriented, functional, programming language that runs on the .Net Framework. The high-level, strongly-typed, general purpose programming language is developed and maintained by Microsoft.

  • Pointers

A pointer is a variable that explicitly stores memory addresses. It can be modified to point to any random address. Although pointers exist in both Java and C#, it is not a first-class language concept in the former.

  • Portability

C# is specifically designed by Microsoft to run and develop applications for its various platforms. Java, on the contrary, offers a great deal of multi-platform support thanks to its machine-independent bytecode.

In any Java program, the code is converted into bytecode by the Java compiler. Then, this compiled bytecode can be executed on any OS having a compatible JRE installed. Source code once written in Java can run on any platform, which is one of its best benefits.

  • Polymorphism

Polymorphism is available by default in the Java programming language. In C#, however, polymorphism can be used only after invoking the virtual keyword in the base class and then invoking the override keyword in the derived class.

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  • Shipping and Installation

A vast number of C# libraries are shipped with a .NET framework installer along with an IDE, typically Visual Studio.

Java, on the other hand, requires the JDK (Java Development Kit) to be installed on a system. It comes with the Java compiler and the JRE (Java Runtime Environment). No pre-packaged IDE is available. Hence, you need to download and install one manually.

  • Source File

It is mandatory for a Java source file to match the name of the only public class inside it. On the contrary, no such rule exists for C#, which also allows for having multiple public classes inside the same source file.

  • Structures and Unions

C# provides support for structures and unions. On the other hand, Java doesn’t provide support for either structures or unions.

  • The strictfp Keyword

Floating point calculations are platform-dependent. There is no way in C# to guarantee that the result of some floating point operation remains identical across platforms. However, Java has the strictfp keyword for serving the same purpose.

Some important points to remember regarding the strictfp keyword are:

  • All methods and nested types declared in any class or interface that is declared using the keyword will implicitly gain the strictfp property
  • Because methods belonging to an interface are abstract implicitly, the keyword can’t be used with a method inside an interface
  • It can be used only with classes, interfaces, and methods
  • Though not usable with abstract methods, it can be used with abstract classes and interfaces
  • Unsigned Primitive Numeric Types

Java has no provision for unsigned primitive numeric types, while C# has. Java’s inability of the feature makes it somewhat unsuitable for low-level programming.

However, it is widely believed in the programming community that mixing signed and unsigned variables can result in bad code quality.

  • User-defined Casts

A cast in programming is simply an explicit conversion. It requires a cast operator. Casting is required when there is a chance of either the information being lost or failure of implicit (automatic) conversion.

The C# programming language provides support for user-defined casts while Java doesn’t.


Though there are several differences between Java and C#, there aren’t any significant speed or performance boosts that one can get from going for either language over the other.

Hence, all about choosing between the two high-level, general-purpose programming languages boils down to the platform of choice for application development as well as the preference of the developer or development team.

Check out top-rated C# tutorials for improving your skills or go for these best Java tutorials to step up your coding prowess.

Have we missed out on some important difference(s) between C# and Java? Or is there some error/misinformation in the article? Please let us know via comments!

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