Java Spec
The rules of the Java language are defined in the Java Language Specification and are enforced by the Java Compiler, javac.
- The output of
javacis platform-neutral bytecode that complies with the Java Virtual Machine Specification.
The JVM doesn't know the Java language - that's the Java Compiler's job.
- It just needs valid bytecode to run.
| Specification | Specifies | Applies To |
|---|---|---|
| Java Language Specification | How Java source code is compiled: rules of Java syntax. | javac - the Java Compiler |
| Java Virtual Machine Specification | How bytecode is executed | java - the JVM |
| Java Platform Standard Edition API Specification | How the Java libraries must be implemented |
Practice Exercise¶
The JRE is almost ubiquitous as an execution platform.
Developers with different ideas about language structure have developed many other languages that compile to JVM bytecode.
- Clojure
- Scala
- Kotlin
- Groovy
