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Java / JVM Architecture (Java21) Interview questions

Define JVM, JRE, and JDK?

These three terms describe increasingly larger packages, each one containing the one before it.

TermWhat it is
JVMThe runtime engine that executes bytecode; it does not include libraries or development tools.
JREJVM plus the core class libraries needed to run (but not build) Java applications.
JDKJRE plus development tools - javac, javap, jshell, and debuggers - needed to build Java applications.

Since Java 11, Oracle stopped shipping a separate standalone JRE package, but the JRE still exists conceptually as the subset of the JDK needed at runtime.

Which of the three includes development tools like javac?
The JRE consists of:

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