Development

Java

Java is an object-oriented, platform-independent programming language that has been among the world’s most used since 1995 – especially in enterprise and Android development.

Java has been one of the world’s most widespread programming languages for almost three decades. From enterprise applications in large corporations to Android apps and big data pipelines – Java is everywhere. The combination of platform independence ('Write Once, Run Anywhere'), a huge ecosystem and proven stability makes Java the first choice for business-critical systems. With modern versions (Java 17+, 21 LTS) and frameworks like Spring Boot, Java is as productive and current as ever.

What is Java?

Java is a statically typed, object-oriented language released in 1995 by Sun Microsystems (now Oracle). The central idea is the Java Virtual Machine (JVM): Java is compiled to bytecode that runs on any platform with a JVM – regardless of OS and hardware. The language offers strong typing, automatic memory management (garbage collection), a large standard library and a mature ecosystem. Java is the base for Spring Boot, Jakarta EE (formerly Java EE) and Hibernate. The JVM also runs other languages (Kotlin, Scala, Groovy). With a six-month release cycle (since Java 9) and LTS versions (11, 17, 21), Java stays current. GraalVM and native compilation (e.g. Quarkus/Micronaut) address the historical criticism of slow startup.

How does Java work?

Java source (.java) is compiled by javac to platform-independent bytecode (.class). The JVM loads and runs the bytecode at runtime. The JIT compiler optimizes hot code to native machine code – so Java can approach C/C++ performance. Garbage collection manages memory and helps avoid leaks. Build tools like Maven and Gradle manage dependencies and build. Spring Boot as the most used framework provides auto-configuration, dependency injection and embedded server (Tomcat) for production-ready microservices in minutes.

Practical Examples

Enterprise backend: An insurer runs its core business logic with Spring Boot microservices communicating via Kafka and managing millions of policies.

Android: Although Kotlin is now preferred, much existing Android code is Java – and the Android API remains Java-compatible.

Big data: Apache Hadoop, Spark and Kafka are written in Java/Scala and form the backbone of modern data pipelines.

E-commerce: Large platforms like eBay and Amazon use Java-based systems for catalogs, orders and payment.

Banking: Many banks run trading systems, risk engines and payment platforms on Java for reliability.

Typical Use Cases

Enterprise software: Business-critical backend systems, ERP integrations and workflow engines

Microservices: Spring Boot and Quarkus for containerized, scalable service architectures

Big data and streaming: Kafka, Spark and Flink for real-time data at scale

Android apps: Native Android and existing app codebases in Java

Financial services: Low-latency trading, compliance engines and payments

Advantages and Disadvantages

Advantages

Platform independence: One bytecode runs on Windows, Linux, macOS and in containers – thanks to the JVM
Huge ecosystem: Hundreds of thousands of libraries, proven frameworks (Spring, Hibernate) and active community
Enterprise-proven: Decades of use in banks, insurers and corporations prove stability and scalability
Talent availability: Java is widely taught – developers are readily available
Modern development: Records, pattern matching, virtual threads (Java 21) and GraalVM keep Java current

Disadvantages

Verbose syntax: Java needs more boilerplate than Kotlin, Python or TypeScript – despite improvements
Startup time: JVM warmup and JIT cause longer startup than Go or Rust – relevant for serverless and CLI
Memory use: Java apps typically need more RAM than comparable Go or Rust programs
Licensing: Since Java 11 Oracle JDK requires a commercial license – alternatives like Eclipse Temurin (Adoptium) are free

Frequently Asked Questions about Java

Is Java still relevant or outdated?

Java is highly relevant. Per TIOBE and Stack Overflow it is consistently in the top 3. Java 21 (LTS, 2023) added virtual threads, pattern matching and more. Spring Boot 3, Quarkus and Micronaut enable cloud-native development. Talent and ecosystem are excellent. For new enterprise projects Java remains one of the best options.

Java or Kotlin – which to choose?

For Android, Google officially recommends Kotlin. For backend with Spring Boot both work well – Spring has first-class Kotlin support. Kotlin offers more concise syntax, null safety and coroutines. Java has the larger ecosystem and more developers. Existing Java projects can adopt Kotlin gradually; both are 100% interoperable.

What is the difference between Java and JavaScript?

Despite the similar name they are very different. Java is a compiled, statically typed language for backend, Android and enterprise. JavaScript is interpreted, dynamically typed and used mainly for web frontend (and with Node.js for backend). The name 'JavaScript' was a 1990s marketing choice – technically they have little in common.

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