Java

Java is a high-level, object-oriented, compiled and interpreted programming language known for its “write once, run anywhere” (WORA) capability via the Java Virtual Machine (JVM). It is widely used in enterprise applications, Android development, and large-scale systems.

Overview

Java was created by James Gosling at Sun Microsystems (later acquired by Oracle and released in 1995. Java code is compiled to bytecode, which runs on any JVM. The ecosystem includes Spring, Hibernate, Maven, and Gradle.

Key Features

  • Platform independence via JVM (Write Once, Run Anywhere)
  • Strong typing and automatic memory management (garbage collection)
  • Rich ecosystem: Spring Framework (enterprise), Grails (full-stack), Hibernate, Maven, Gradle
  • Enterprise frameworks: Spring Framework, Grails
  • Concurrency support with threads and the java.util.concurrent package
  • Extensive standard library and enterprise APIs
  • Android app development (Kotlin is now preferred, but Java is still widely used)

Licensing

Java has a dual model:

  • OpenJDK: The open-source reference implementation of Java SE, released under the GPL v2 with Classpath Exception. Free and open source.
  • Oracle JDK: Oracle’s commercial distribution with additional features and support. Requires a commercial license for production use (changed in JDK 11+).

See OpenJDK for the open-source version and Oracle JDK FAQs for licensing details.

Official Resources