What is JRE, JDK and JVM? Explain in detail.

Answer 1

-JDK(JAVA DEVELOPMENT KIT): Is a software development environment used for developing Java applications and applets. It includes the Java Runtime Environment (JRE), a compiler (javac), an archiver (jar), a documentation generator (Javadoc), and other tools needed in Java development.
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-JRE(JAVA RUNTIME ENVIRONMENT): 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.
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JVM(JAVA VIRTUAL MACHINE):

***A specification where the 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.
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Answer 2

In the past, it was possible to download the JRE separately, but since Java 11 SE this option is not available and the JRE as a term loses its meaning.