Java

Java is a statically typed, object-oriented language developed at Sun Microsystems (now Oracle) and first released in 1995. Its core promise, Write Once, Run Anywhere, means source code compiles to platform-neutral bytecode that runs on any system with a Java Virtual Machine (JVM), with no recompiling per platform. Automatic garbage collection, with collectors such as G1 and ZGC for different latency needs, manages memory.

The JVM ecosystem reaches beyond Java itself: Kotlin, Scala, Groovy, and Clojure run on it too. Frameworks such as Spring Boot, Quarkus, and Micronaut, the Hibernate ORM, and the Maven and Gradle build tools are mature and widely documented. Java is a standard choice for banks, insurers, and large SaaS backends where long-term maintainability matters, and it remains central to Android development.

The language has modernised steadily. Records, pattern matching, sealed classes, text blocks, and switch expressions cut boilerplate, and Virtual Threads (Java 21) make high-concurrency servers simple to write with plain sequential code. Java 25, the current long-term support release, finalized Scoped Values, flexible constructor bodies, and compact object headers, with Structured Concurrency still in preview. GraalVM Native Image compiles applications ahead of time into native executables that start in milliseconds.

New versions ship every six months, with a long-term support release every two years (11, 17, 21, 25) that most production systems target. OpenJDK is free under GPLv2 with the Classpath Exception, and Temurin, Corretto, and other distributions are free to use commercially.