What are the differences between C# and Java?

Jan 13, 2022 - 6 min read
Crystal Song

In this article, we’ll be comparing the merits of two popular programming languages side-by-side: Microsoft’s C# and Oracle’s Java. At their core, C# (pronounced see sharp) and Java are both robust, high-level, object-oriented programming languages with more similarities than differences. One significant advantage to learning either language is that their fundamental similarities make it relatively easy to learn one language after mastering the other.

Together, we’ll look at a brief history of the two programming languages in question, their different applications, strengths, and what resources to explore to deepen your understanding of C# and Java.

Let’s jump right in!

We’ll cover:

C# and Java: A brief history

Origins of C#

C# was first developed in 2000 as a direct competitor to Java by Anders Hejlsberg and his team at Microsoft. Like Java, C# was based on the C and C++ programming languages, referenced by its original name, “C.O.O.L.,” or “C-like Object Oriented Language,” but was designed with business and enterprise needs in mind.

In 2005, version 2.0 of C# introduced features generics and iterators to catch up to Java. Version 2.0 also introduced other major features such as partial types, anonymous methods, nullable value types, covariance, and contravariance. Though the first few versions of C# shared many similarities with C++ and Java, later releases helped distinguish C# as a unique language capable of facilitating object-oriented and functional programming.

Although C# was originally closed-source and exclusive to development in the Microsoft ecosystem, new features and open-source tools were added to support cross-platform development.

Origins of Java

James Gosling began the development of Java at Sun Microsystems (later acquired by Oracle) as an alternative to the C++ programming language, with its first public implementation in 1995.

Java’s design requirements were centered around enabling the creation of robust and secure applications across multiple platforms while consuming the least amount of system resources. In addition, Gosling sought to create a language platform that would be simple and familiar to programmers, allowing them to grasp the fundamental concepts of the language quickly.

What emerged was a highly reliable, open-source programming language that has proven ideal for developing network-based end-user applications across a wide range of environments.

Overview and applications: C# vs. Java

What is C#?

C# is a high-level, general-purpose, object-oriented, and notably, it is the first component-oriented programming language. Like Java, C# is popular because it is versatile, easy to learn, and enjoys the support of a large community that has made many contributions to developing new C# tools and software.

As a multi-paradigm programming language, C# supports object-oriented programming in addition to functional, structured, imperative, reflective, and concurrent programming paradigms.

C# programs run on the .NET Framework, which has two main components:

  • .NET Framework
    • .NET Framework Class Library (FCL)
      • Frameworks
      • Utility features written in .NET
      • Wrappers around OS functionality
    • Common Language Runtime (CLR)

The .NET Framework class library (FCL) is a collection of different classes, interfaces and data types used to design .NET applications.

The Common Language Runtime (CLR) uses just-in-time (JIT) compilation to compile the C# code used for .NET applications.

Common applications of C#:

  • Game development
  • Microsoft applications
  • Web applications
  • Desktop applications
  • …and more!

What is Java?

Java is a high-level, general-purpose, object-oriented programming language. Java is popular amongst application developers because of its simplicity, versatility, and portability. Thanks to its large and well-established community, anyone looking to start a Java project will find that they have access to a massive collection of useful open source libraries and tools.

The Java Platform or Java Development Kit (JDK), is the software development environment used to build and run Java applications and components. The JDK can be deployed on Windows, macOS, Linux, and Solaris.

You can think of the Java Platform as a series of nested packages:

  • Java Development Kit (JDK)
    • Java Runtime Environment (JRE)
      • Java Virtual Machine (JVM)
      • Libraries
      • Development tools (javac, java, etc.)
      • Other files

The Java Runtime Environment (JRE) is an installation package that sets up an environment where you can only run a Java program or application. The JRE contains class libraries, loader classes, and the JVM.

The Java Virtual Machine (JVM) is an interpreter and provides a runtime environment for your code. The JVM is a critical part of both the JDK and JRE, as it is responsible for going through each line of a Java program to execute it.

Common applications of Java:

  • Front-end web development
  • Back-end web development
  • Mobile applications
  • Big data analytics
  • Scientific computation applications
  • Machine learning
  • Data science
  • …and more!

Comparing C# and Java


For the most part, C# and Java are reasonably similar because they’re both high-level, object-oriented programming languages descended from C and C++.

C# and Java share:

  • Similar syntax (e.g., static, class, int)
  • Advanced features like garbage collection
  • Multiple class inheritance
  • Cross-platform functionality
  • Intermediate language code generation
    • C# compiler generates Microsoft Intermediate Language (MSIL)
    • Java compiler generates Java bytecode
  • OOP concepts
    • Encapsulation
    • Abstraction
    • Inheritance
    • Polymorphism

Comparison chart: C vs. Java

Features of comparison C# Java
Programming paradigm Object-oriented, component-oriented, functional, strong typing Object-oriented
Runtime environment Common Language Runtime (CLR) Java Virtual Machine (JVM)
Platform dependency Cross-platform (Windows preferred) Cross-platform
Checked exceptions Not supported Supported
Enumerations Supported with the yield statement Not supported
Pointers Supported in unsafe mode Not supported
Conditional compilation Supported Not supported
Structure and union Supported Not supported
Arrays Specialization of Object Specialization of System
goto statement Supported Not supported
strictfp keyword Not supported Supported

Which language should I learn?

Although C# and Java share enough similarities that it won’t put you at a disadvantage to learn one and not the other, each language does possess certain strengths that are important to take into consideration.

Here are some questions to ask when deciding between C# and Java:

  • What platform am I developing on?
  • What types of applications will I be making?
  • Is there a tool I want to use?
  • Are there industry-specific preferences?
  • Does the company I want to work for have a preference?

Consider learning Java first if you want to create highly complex web applications or work with Android apps. Also, let’s not forget that Java’s slogan is “Write once, run anywhere”! If portability is a top priority, Java is a clear winner. On the other hand, if you plan on developing games or working in the Microsoft ecosystem, it may be more advantageous to start out with C#.

Wrapping up and next steps

If you want to learn more about C# or Java, check out our courses and learning paths! Educative’s learning paths are designed to help you develop valuable, practical skills at your own pace with interactive challenges and exercises.

  • Java for Programmers is a great way to familiarize yourself with the Java programming language. This course is perfect for people who have programming experience but are new to Java.
  • C# for Programmers: A Practical Guide introduces you to fundamental programming concepts found in C#, such as loops, arrays, and object-oriented programming.

Happy learning!

Continue learning about C# and Java

WRITTEN BYCrystal Song

Join a community of 500,000 monthly readers. A free, bi-monthly email with a roundup of Educative's top articles and coding tips.