- The Java Development Kit (JDK) is a software development environment used for developing Java applications and applets. It includes the Java Runtime Environment (JRE), an interpreter/loader (Java), a compiler (javac), an archiver (jar), a documentation generator (Javadoc) and other tools needed in Java development.
JAVA RUNTIME ENVIRONMENT
- JRE stands for “Java Runtime Environment” and may also be written as “Java RTE.” The Java Runtime Environment provides the minimum requirements for executing a Java application; it consists of the Java Virtual Machine (JVM), core classes, and supporting files.
JAVA VIRTUAL MACHINE
- A specification where working of Java Virtual Machine is specified. But implementation provider is independent to choose the algorithm. Its implementation has been provided by Sun and other companies.
- An implementation is a computer program that meets the requirements of the JVM specification
- Runtime Instance Whenever you write java command on the command prompt to run the java class, an instance of JVM is created.
- The JVM doesn’t understand Java source code, that’s why you compile your
*.javafiles to obtain
*.classfiles that contain the bytecodes understood by the JVM. It’s also the entity that allows Java to be a “portable language” (write once, run anywhere).