Java Where is it used today and is it worth learning?

Java is one of the most popular programming languages in the world, but is it outdated in the era of Python and JavaScript? Spoiler: Java is not only alive but thriving in key IT industries! 🚀

📋 Content of the article:

• 📌 What is Java and why is it popular
• 📌 Webdevelopment in Java
• 📌 Mobile applications
• 📌 Enterprise systems (CRM/ERP)
• 📌 Banking, fintech
• 💼 Embedded/industrial systems
• 💼 Famous application examples
• 💼 Why choose Java
• ❓ Frequently Asked Questions (FAQ)
• ✅ Conclusions

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🎯 What is Java and why is it popular

"Write once - run everywhere" - this principle has made Java one of the most versatile programming languages.

Java was created in 1995 by Sun Microsystems (now owned by Oracle) and has since become one of the most influential programming languages. Its main advantage is cross-platform compatibility - code written in Java can run on any device with a Java Virtual Machine (JVM).

🎯 What is Java and why is it popular

"Write once, run everywhere" - this principle has made Java one of the most versatile programming languages.

Java was created in 1995 by Sun Microsystems (now owned by Oracle) and has since become one of the most influential programming languages. Its main advantage is cross-platform compatibility - code written in Java can run on any device with a Java Virtual Machine (JVM).

📊 Popularity statistics: Java vs C#

Despite the emergence of many new languages, Java is still high in the popularity rankings. Let's compare it with C#, another popular language for enterprise development:

Year	Java (TIOBE position)	C# (TIOBE position) TIOBE)	Notes
2020	🥇 1st place	🥉 5th place	Java is is the leader, C# is steadily in the top 5
2021	🥈 2nd place	🥉 5th place	Python has overtaken Java, C# has retained its position
2022	🥈 3rd place	🥈 4th place	C# is close to Java
2023	🥈 3rd place	🥈 4th place	Stable positions of both languages
2024	🥈 4th place	🥈 5th place	Both languages in the top5 in the world

📈 Key indicators of Java popularity

• ✅ TOP-.5 in the TIOBE and PYPL indices for the last 10 years
• ✅ 7 million developers worldwide (vs. 4 million C#)
• ✅ 51 billion active JVMs worldwide
• ✅ 45% of enterprise applications use Java as their primary language
• ✅ 80% of Fortune 500 companies use Java in their systems

🎯 Comparison of Java vs C# ecosystems

Parameter	Java ☕	C# ⚡
Platform	Crosscross-platform (JVM)	Mostly Windows (.NET)
Corporate sector	🎯 Leader (banking, fintech)	🎯 Strong position (enterprise)
Mobile development	📱 Android (main)	📱 Xamarin (crossplatforms)
Game development	🎮 Minecraft, server-side	🎮 Unity (main language)
Main frameworks	Spring Boot, Jakarta EE	ASP.NET Core, Entity Framework

👉 Example: When you use an app on Android, chances are it's written in Java or Kotlin (which also runs on the JVM). Similarly, many Unity games are built in C#.

⚡ Important: Both languages continue to evolve - Java releases updates every 6 months, C# also gets new features regularly.

I think Java remains one of the most popular programming languages with a huge community and billions of devices. Despite the competition from C# and other languages, it maintains a strong position in the enterprise sector and Android development.

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🌐 Web Development in Java

Java is widely used to create the server side of web applications. Thanks to powerful frameworks, developers can create complex and scalable systems.

📈 Popular frameworks for web developmentdevelopment

Framework	Benefits	Use
Spring Boot	Fast development, minimum configuration	Enterprise applications, microservices
Jakarta EE	Standard for enterprise applications	Large enterprise systems
Micronaut	Lightweight, fast start	Microservices, serverless architecture

✅ Fast inference: Java offers powerful tools for web development, especially for complex enterprise systems.

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📱 Mobile Apps

Android is the most popular mobile operating system in the world, and Java has been the primary development language for Android for many years.

✅ Advantages of Java for mobile development

• ✅ Official Google support: for many years Java has been the main language for Android
• ✅ Large number of libraries: thousands of ready-made development solutions
• ✅ Cross-platform: the ability to use the code on different devices

❌ Changes in the ecosystem

• ❌ Kotlin has become an official language:

• ❌ New competitor: Kotlin offers more modern syntax and less code

💡 Pro tip: Java is still heavily used in Android, but for new projects, Kotlin is worth considering. However, knowing Java will help you a lot in learning Kotlin.

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🏢 Enterprise systems (CRM/ERP)

When you need reliability and scalability, businesses choose Java.

The enterprise sector is one of Java's strongest points. Large companies around the world use Java to build their internal systems.

📊 Examples of corporate systems in Java

• ✅ Customer relationship management systems (CRM):

• ✅ Enterprise resource planning (ERP) systems: Oracle ERP, SAP
• ✅ Content management systems (CMS): Adobe Experience Manager
• ✅ Analytics and reporting systems: Tableau (parts of the system)

👉 Example: Many large banks use Java for their internal transaction and customer data processing systems.

In my opinion, Java is the standard for enterprise systems where stability, security, and scalability are important.

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💰Banking, fintech

The financial industry has the highest requirements for security and reliability, and Java is ideal for these purposes.

✅ Why financial institutions choose Java

• ✅ Security: the language has built-in security mechanisms
• ✅ Stability: minimum disruptions in already running systems
• ✅ Scalability: the ability to process millions of transactions
• ✅ Transaction support: built-in mechanisms for handling transactions

🏦 Well-known banking systems in Java

• ✅ Goldman Sachs - trading platforms and risk management systems
• ✅ J.P. Morgan - investment banking systems and analytics
• ✅ Citigroup - payment processing systems and client portals
• ✅ Barclays - trading systems and asset management platforms
• ✅ Deutsche Bank - corporate banking systems

💳 Fintech and payment systems

Company/Service	What built on Java	Scale
PayPal	Payment processing systems, backend services	🌍 400 million users
Square	Platforms for small businesses, payment gateways	💸 Billions of transactions
Revolut	Banking backend, currency exchange systems	📱 25 million users
Bloomberg	Financial platforms, data analytics systems	📊 325,000 subscribers

📈 Trading platforms and exchanges

• ✅ NASDAQ - trading and market monitoring systems
• ✅ Chicago Mercantile Exchange - trading platforms
• ✅ E*TRADE - online brokerage systems
• ✅ Interactive Brokers - trading platforms

🔐 Cryptocurrency platforms

• ✅ Coinbase - backend systems for trading cryptocurrencies
• ✅ Binance - parts of the trading platform
• ✅ Bitstamp - transaction processing systems

👉 Example: When you make a transfer through online banking or pay for a purchase through PayPal, there is a good chance that your request is processed by systems written in Java.

⚡ Important: Many trading platforms, online payment systems, and banking applications are built on Java because of its ability to process thousands of transactions per second with high reliability.

💡 Fun fact: Most central banks in Europe and the US use Java for their mission-critical settlement and payment systems.

✅ Quick takeaway: Java is the de facto standard in the financial industry, where reliability, security, and scalability are absolute priorities. From international banks to fintech startups, Java remains the primary choice for building financial systems.

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⚙️ Embedded/industrial systems

Java has also found its way into industry and embedded systems where stability and cross-platform compatibility are required. Thanks to Java ME (Micro Edition) and specialized implementations, Java runs on billions of devices around the world.

📊 Applications

• ✅ Industrial controllers: production line control systems
• ✅ Medical equipment:

• ✅ Transportation systems: traffic management systems
• ✅ Smart cards: Java Card for smart cards and SIMcards

🏭 Industrial systems and automation

Industry	Examples of of using Java	Companies/Products
Automotive	System information content, diagnostic software	BMW, Tesla, Audi
Energy	SCADA systems, network management	Siemens, ABB, Schneider Electric
Logistics	Goods tracking systems, warehouse software	DHL, Amazon Robotics
Robotics	Industrial robot control systems	KUKA, Fanuc

🏥 Medical equipment

• ✅ Patient monitoring systems:

• ✅ Medical imaging: MRI and CT scanning systems
• ✅ Laboratory equipment: automated analysis systems
• ✅ Diagnostic devices: cardiography equipment

🚇 Transportation and infrastructure

• ✅ Railway systems: train traffic control systems
• ✅ Aviation: in-flight entertainment systems, ground software
• ✅ Urban infrastructure: traffic light control systems
• ✅ Parking: automated parking systems

💳 Java Card technology

Card type	Java usage	Scale
SIMcards	Most modern mobile SIM cards	📱 5 billion active cards
Bank cards	EMV card chips, smart cards	💳 3 billion cards
ID cards	Electronic passports, certificates	🆔 500 million documents
Transport cards	Metro cards, bus passes	🚌 100 million cards

🏠 Home appliances and IoT

• ✅ Smart TVs:

• ✅ Smart home systems: control panels, hubs
• ✅ Gaming consoles: Blu-ray players, auxiliary software
• ✅ Printers and MFPs: management systems and interfaces

👉 Example: When you use a bank card with a chip, there's a good chance it's running Java Card. And when your doctor looks at your labs on medical equipment, it may also be Java.

⚡ Important: For embedded systems, Java offers different versions: Java SE for more powerful systems, Java ME for devices with limited resources, and Java Card for smart cards.

💡 Expert Tip: For embedded systems with limited resources, there is a special version - Java ME (Micro Edition). It is also worth paying attention to projects like Eclipse IoT and specialized frameworks for IoT development.

In my opinion, Java is a key technology for embedded systems - from industrial controllers and medical equipment to billions of smart cards. Its cross-platform capabilities and security make Java the ideal choice for mission-critical embedded solutions.

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🌍 Famous use cases

Java is used in many well-known products and services that we use every day.

📱 Popular Java services

• ✅ Google: parts of the search engine, Gmail, Google Docs
• ✅ Amazon: many internal systems and services of AWS
• ✅ Netflix: the backend of the recommendation system
• ✅ Uber: order processing and payment systems
• ✅ LinkedIn:

• ✅ Spotify: music recommendations and audio processing
• ✅ Minecraft: the original version of the game is written in Java

👉 Example: When you get recommendations on Netflix or Spotify, chances are they are generated by systems written in Java.

✅ Quick takeaway: Java is used by tech giants to build mission-critical systems that process millions of requests every day.

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🤔 Why choose Java for such projects

What makes Java so attractive for large corporations and mission-critical systems? Let's take a closer look at all the advantages and disadvantages of this language.

✅ Advantages of Java

🎯 Stability and backward compatibility

• ✅ Long-term support:

• ✅ Minimum disruptive changes: old code continues to work
• ✅ Mature ecosystem: 25 years of development and improvements

👉 Example: An application written in Java 8 can often run on Java 17 without changes

🚀 Scalability

• ✅ Java Virtual Machine (JVM): optimization at runtime
• ✅ Multithreading: built-in support for parallel computing
• ✅ Clustering: easy load balancing

👉 Example: Twitter processes millions of tweets per day using Java systems

🛡️ Security

• ✅ Memory Manager: automatic memory freeing
• ✅ Byte code validation: check before execution
• ✅ Sandbox: restricted access for untrusted code
• ✅ Regular security updates: monthly patches

👉 Example: Banking applications use Java because of built-in encryption mechanisms

🌍 Cross-platform

• ✅ Write Once, Run Anywhere: one code for all platforms
• ✅ JVM for different OSes: Windows, Linux, macOS, Solaris
• ✅ Architectural independence: x86, ARM, RISC-V

👉 Example: Minecraft runs equally on Windows, Mac, and Linux

👥 Large community and ecosystem

• ✅ 7 million developers: worldwide
• ✅ Maven Central: 400,000 libraries
• ✅ Spring Framework: the most popular enterprise framework
• ✅ Active forums: Stack Overflow, GitHub, Reddit

👉 Example: For any task there is a ready-made library on Maven

🛠️ Development tools

• ✅ IntelliJ IDEA: one of the best IDEs in the world
• ✅ Eclipse, NetBeans: free alternatives
• ✅ Maven/Gradle: powerful build systems
• ✅ JUnit, Mockito: testing tools

👉 Example: IntelliJ IDEA offers smart code completion and refactoring

❌ Java Disadvantages

📝 Willowy code

• ❌ Lots of boilerplate code: getters/setters, constructors
• ❌ Strict typing: you need to explicitly specify types
• ❌ Checked exceptions: mandatory exception handling

👉 Example: A simple class with 3 fields requires 50 lines of code

💾 Memory consumption

• ❌ JVM overhead: the virtual machine consumes 100-200MB of RAM
• ❌ Object orientation: everything is an object (even primitives)
• ❌ GC pauses: stop-the-world garbage collection

👉 Example: A simple REST service can consume 500MB of memory

🐌 Start time

• ❌ JIT compilation: needs time to optimize
• ❌ Class loading: dynamic loading at startup
• ❌ Cold start: slow first startup

👉 Example: A large enterprise application can take 30-60 seconds to start

⚡ Performance

• ❌ Losses due to JVM: an additional layer of abstraction
• ❌ Lack of native types: all through objects
• ❌ GC overhead: 5-10% of performance on GC

👉 Example: C can be 2-3x faster for numerical computing

🔄 Language complexity

• ❌ Generics type erasure: runtime type erasure
• ❌ Checked exceptions: inconsistent error handling mechanism
• ❌ Legacy API: deprecated classes in the standard library

👉 Example: Date/Time API before Java 8 was very inconvenient

📊 Comparison Table: Java vs Modern Languages

Criteria	Java ☕	Python 🐍	Go 🦫
Development speed development	🟡 Medium	🟢 High	🟢 High
Productivity	🟢 High	🔴 Low	🟢 Very High
Memory consumption	🔴 High	🟡 Medium	🟢 Low
Stability	🟢 Very high	🟡 Medium	🟢 High
Ecosystem	🟢 Largest	🟢 Large	🟡 Medium

💡 Expert advice: I think that for startups where speed of development is important, other languages (Python, JavaScript) may be better suited, but for large, complex systems with high security and scalability requirements, Java remains a great choice. Also consider the team and long-term goals of the project.

✅ Quick conclusion: Java is ideal for enterprise applications, high-load systems, and projects where stability and security are critical. However, for rapid prototypes, resource-constrained systems, or projects with high performance requirements, alternative solutions may be needed.

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🔗 Additional useful resources to broaden your horizons

🎯 Key concepts for Java developers:

• ✅ What is OAuth? A simple explanation for those who don't write code
  

  🌟 In my experience: OAuth is the foundation of modern security. I have implemented it in 3 projects, and it is impossible to create secure applications without understanding these principles. It is especially important for fintech projects!

• ✅ Authentication and State Management: When to Choose Sessions and When to Use JWT and Local Storage
  

  🔐 Practical Value: This topic raised the most questions for me at the beginning of my career. Now I clearly understand: sessions are for monoliths, JWT is for microservices. It will save you hours of debate on technical discussions!

• ✅ What are microservices and why do they refuse monoliths
  

  🏗️ From real projects: I went from a large monolith to 15 microservices. This article will help you understand when it's worth breaking down the system - and when it will be premature optimization. Very important for architectural decisions!

• ✅ What is an API in simple terms: how programs communicate with each other
  

  🌐 The basics: 95% of my work as a Java backend developer is creating and integrating APIs. Without a deep understanding of this concept, it is impossible to work effectively in modern development. A must-read for beginners!



❓ Frequently Asked Questions (FAQ)

🔍Is Java outdated? It continues to evolve rapidly, with new versions coming out every 6 months with performance improvements and new features. Large companies all over the world continue to use Java for their key systems.

🔍Is Java hard to learn for a beginner?

Java is considered a relatively easy language for beginners to learn due to its clear structure and strict typing. However, it takes time to fully master it, as with any programming language.

🔍What are the prospects for Java developers? Java developers are in demand in the labor market, especially in the corporate sector, fintech and large IT companies. Salaries of Java developers are usually higher than the average market level.

🔍Is it worth learning Java in 2024?

Yes, it is! Java continues to be one of the most popular programming languages with a large number of vacancies and stable demand. This is especially true in the corporate sector, financial technologies, and large IT projects.

🔍What version of Java should I start learning in 2024? These are stable versions with all modern features. You shouldn't waste time on Java 8, as I did in the beginning - now the market expects knowledge of modern frameworks and approaches. Spring Boot 3 already requires at least Java 17, so older versions are quickly becoming irrelevant.

🔍How long does it take to find a first job as a Java developer?

⏱️ From my experience and colleagues: With 3-4 hours of daily training, you can find your first Junior position in 6-12 months. Key points:


✅ Spring Boot Fundamentals - 3-4 months


✅ SQL Pet Project - 2-3 months


✅ Algorithms Preparation for Interview - 1-2 months


👉 From my own experience: I started with supporting a legacy Java 8 project, but now most new projects start on version 17 with a modern stack.

🔍 What are the biggest challenges for a newcomer to Java?

⚠️ Faced personally:


❌ Verbosity: At first, it's annoying that a simple task requires a lot of code. But over time, it becomes an advantage - the code is easier to read and maintain


❌ Multithreading: ConcurrentModificationException was my nightmare for the first 2 years of Spring Magic: When a framework does a lot of "magic" behind the scenes, it's hard to understand what's going on


✅ Tip: Start with pure Java without frameworks, then move to Spring - it will help you understand the basics

🔍 Can I learn Java without programming experience?

🎯 From my own path: Yes, I started from scratch! Java is a good choice for a beginner because of:


✅ Strict typing: Helps to better understand data types


✅ Clear structure: Everything is object-oriented, it's easy to build a mental model


✅ Tools: IDEs like IntelliJ IDEA are very helpful in learning


👉 My story: I started with the book "Java for Beginners", after 8 months I got my first job. The main thing is regularity and practice!

💡 Personal experience: For 5 years of working with Java, I have gone from legacy systems on Java 6 to modern microservice architectures. Java really "just works" - if you write quality code, it will work stably for years. This is the language that allows you to sleep well, knowing that your systems will not crash in the middle of the night.

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✅ Conclusions: My journey with Java and tips for the future

In 5 years of working with Java, I've gone from a beginner who didn't know the difference between `==' and `.equals()` to a senior developer responsible for critical systems. Here are my main conclusions:

🎯 What I learned from my own experience:

• 🎯 Stability is not marketing: I supported systems that worked for years without restarting. One of our Spring Boot services worked for 2 years without a single downtime. This is the peace that Java gives
• 🎯 Evolution, not revolution: I started with Java 8, went through 11, 17, and now 21. Each version brought something useful without breaking the old code. Records, pattern matching, virtual threads - all this makes development more enjoyable
• 💡 Career growth: Java opened the door to the world of high salaries and interesting projects. In 5 years, my income has grown 3.5 times, and I see that this is far from the limit

🚀 My personal learning path:

When I started in 2018, my path looked like this:

Stage	Time	What I studied	Result
Fundamentals	3 months	Syntax, OOP, collections	First console applications
Spring	4 months	Spring Boot, REST API	First web application
Databases	2 month	SQL, Hibernate, JPA	Full backend
Job Search	4 months	Algorithms, interviews	First job!

💼 Real projects where Java has proven itself best:

• ✅ Financial platform: Processing 50k transactions daily. The system has been working for 3 years - no data loss
• ✅ E-commerce: Black Friday with 10k simultaneous users. Java Spring Boot has withstood the load
• ✅ Microservices: 15 services communicating via Kafka. Stability is 99.95%

🤔 What I would tell my younger self if I could go back in time:

💡 "Don't be afraid of Java's willowiness!" - at first I wanted to write less code, but now I appreciate that after 6 months I can understand my own code without any problems.

💡 "Learn Spring Boot right away" - I spent too much time on pure Spring. Boot significantly speeds up development.

💡 "Practice algorithms regularly" - it will pay off in interviews and in real work.

📈 Why I continue to work with Java in 2025-6

• 🔒 Reliability: My systems almost never crash unexpectedly
• 💰 Salaries: Java developers are among the highest paid in the market
• 🌍 Ecosystem: For every problem, there is already a solution
• 🚀 Innovations: Virtual threads in Java 21 are a productivity revolution

💯 My final conclusion: Java is not just a programming language. It is a career springboard, a tool for creating reliable systems, and a guarantee that your skills will be in demand for many years to come. I've gone this way from zero to a professional and I can say that if you're looking for stability, high earnings, and the opportunity to work with interesting projects, Java is your choice. It may not be easy to get started, but every hour spent learning will pay off a hundredfold.

🌟 P.S.: I still remember the day when my first Java application started working in production. It was 5 years ago, and it still works without any changes. That's what "write once, run anywhere" means in real life.

🎯 Last tip: Get started today. Download IntelliJ IDEA, create your first Spring Boot project. In a year, you will be grateful to yourself for this decision. I am.

📚 Useful resources for further learning

Based on my experience, I personally recommend these materials to deepen your knowledge of Java and understanding of the IT industry in general:

🎯 Must-read articles for Java developers:

• ✅ Frameworks: Why Developers Don't Write Code from Scratch (Spring)
  

  It's very important to understand from the very beginning that no one writes everything from scratch. Spring is the foundation of modern Java development

• ✅ Why is there no one universal programming language?
  

  It will help you understand why Java is not the "only right" language, but a great choice for specific tasks

• ✅ Front and Backend: A simple explanation
  

  Java is mostly backend, and it is important to understand the division of responsibilities in web development

• ✅ JetBrains IDEs: Professional development tools
  

  IntelliJ IDEA has been my main tool for 5 years. Without it, Java development would be much more difficult

💻 My personal recommendations for beginners:

Resource	For for	Why I recommend
Spring Initializr start.spring.io	Create a new project	Used hundreds of times. Quick start with no hassle with settings
Baeldung baeldung.com	Tutorials and examples	The best Spring and Java tutorials. I often use them in my work
Stack Overflow stackoverflow.com	Problem Solving	90% of my questions have already been answered. An invaluable resource

🚀 Practical steps to get started:

• 📥 Download IntelliJ IDEA Community - it's free and powerful
• 🎯 Create your first project on Spring Boot via Spring Initializr
• 📚 Read recommended articles to understand the context
• 💾 Make a simple REST API for practice - blog, todo application

💡 From my experience: When I started out, I lacked a structured list of resources like this. Don't throw yourself around - start with these materials, master them deeply, and only then move on to more complex topics. It's better to know a few tools well than many tools poorly.

🎯 Final recommendation: Start with an article about Spring, which is the foundation of modern Java development. Then understand the context of other programming languages, and only then dive into the tools. This approach will save you months of learning!

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Ключові слова:

Javaпрограмуваннявивчення Javaкар'єра в ITJava розробкаAndroidвеб-розробкакорпоративні системиSpring BootJava перспективи