[Java basic interview questions] The difference between jdk, jre, and jvm
jdk
Conceptually speaking, JDK is a JAVA development tool. Use it to develop JAVA programs. There are many basic class libraries and jre in it.
JDK (Java Development Kit), which is a fully functional Java SDK, is provided to developers and can create and compile Java programs. It includes JRE, as well as the compiler javac that compiles java source code, and some other tools such as javadoc (document comment tool), jdb (debugger), jconsole (visual monitoring tool based on JMX), javap (decompilation tool) )etc.
JRE
JRE is a JAVA running environment. The developed JAVA program can run as long as it has JRE (jvm).
jvm
JVM is a JAVA virtual machine and is part of the JRE. Operations on JAVA classes are basically completed on the JVM.
The JVM has specific implementations for different systems (Windows, Linux, macOS) with the goal that using the same bytecode they will all give the same results. Bytecode and JVM implementation of different systems are the key to "compile once, run anywhere" of the Java language.