# Java Class Library

> standard library for Java and other JVM programming languages

**Wikidata**: [Q115576](https://www.wikidata.org/wiki/Q115576)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Java_Class_Library)  
**Source**: https://4ort.xyz/entity/java-class-library

## Summary
The Java Class Library is the standard library for the Java programming language and other JVM programming languages. It is a software library classified as free software, licensed under the GNU General Public License, version 2.0. It serves as a foundational component for the Java virtual machine ecosystem.

## Key Facts
- **License:** GNU General Public License, version 2.0 (since May 8, 2007).
- **Platform:** Java virtual machine (JVM).
- **Category:** Instance of a standard library, software library, Java software library, and free software.
- **Primary Language:** Java.
- **Copyright Status:** Copyrighted.
- **Aliases:** Java standard library, Java APIs, Java类库 (Java Class Library in Chinese).
- **Associated Language:** Used by Java (object-oriented programming language, inception 1995).
- **Wikipedia Presence:** Available in English, French, and Japanese.

## FAQs
### Q: Is the Java Class Library free to use?
A: Yes, it is classified as free software. It has been licensed under the GNU General Public License, version 2.0, since May 8, 2007.

### Q: What platforms does the Java Class Library support?
A: The library is designed for the Java virtual machine (JVM). Consequently, it is used by Java and other programming languages that operate on the JVM.

### Q: How is the Java Class Library related to the Java language?
A: It is the standard library for the Java programming language. While it is written in Java and used by it, the library acts as a distinct software layer that enables the language to function on the Java virtual machine.

## Why It Matters
The Java Class Library is a critical infrastructure component in the software development world. As the standard library for Java—one of the most ubiquitous object-oriented programming languages—it provides the essential building blocks and APIs necessary for developers to build functional applications without reinventing basic utilities. Its availability under the GNU General Public License (GPL) since 2007 marked a significant shift toward open-source transparency for the ecosystem, allowing users to freely run, study, change, and distribute the software.

Furthermore, the library's compatibility with the Java virtual machine extends its utility beyond just the Java language; it serves as a resource for other JVM-based programming languages. This interoperability makes it a central hub in the JVM ecosystem, bridging various languages into a cohesive runtime environment. Its status as both copyrighted and free software ensures that it remains protected yet accessible, maintaining a balance between intellectual property control and community-driven development.

## Notable For
- **Standardization:** Acts as the official standard library for the Java programming language.
- **Open Licensing:** Notable for its adoption of the GNU General Public License, version 2.0, in 2007.
- **Cross-Language Support:** Functions as the standard library not just for Java, but for other JVM programming languages.
- **Ecosystem Integration:** Deeply integrated into the Java virtual machine platform.

## Body
### Definition and Classification
The Java Class Library is defined as the standard library for the Java programming language. In the hierarchy of software classification, it is an instance of a **software library**, a **Java software library**, and **free software**. It is categorized technically as a **standard library**, serving as the core collection of utilities available to developers working within the Java environment.

### Licensing and Open Source Status
The library operates under the **GNU General Public License, version 2.0**. This licensing arrangement became effective on **May 8, 2007**, as confirmed by announcements from the OpenJDK community. As free software, it is distributed under terms that permit users to freely run, study, change, and distribute it and any modified versions. Despite being free software, the library retains a **copyrighted** status.

### Technical Environment
The Java Class Library is strictly associated with the **Java virtual machine (JVM)**. While its primary association is with the **Java** programming language (an object-oriented language inceptioned in 1995), it is also utilized by other JVM programming languages. This cross-compatibility makes it a versatile tool in the broader JVM ecosystem.

### Naming and Identity
The entity is recognized globally by various titles, reflecting its widespread use. Aliases include **Java standard library**, **Java APIs**, and **Java类库** (Chinese). It is identified in academic and knowledge databases such as Wikidata and Freebase (ID: /m/02r6_6h). Its documentation and description are maintained across multiple Wikipedia languages, including English, French, and Japanese.

## References

1. [Source](http://mail.openjdk.java.net/pipermail/announce/2007-May.txt)
2. Freebase Data Dumps. 2013