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My understanding of JDK, JRE and JVM

After my in-depth analysis, this is how I understand the JDK, JRE, and JVM. Please correct me if I am wrong ...

  • JVM is a subset of JRE, JRE is a subset of JDK.
  • The JVM is used to convert byte code (* .class) to object code (machine code) using the JRE.
  • The JRE supports the operating system (OS) DLL, which is used by the JVM to convert byte code to object code.
  • Assuming tomorrow that if some new OS starts up, then the available JREs may not support the JVM for byte code for machine code conversion. Therefore, the JRE may need to strengthen support for the new future OS.
  • So, from my analysis above, I conclude that the JVM is common to all OSs, but the JRE has an OS-specific DLL that the JVM will use during byte code to convert object code.
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The JVM is virtual, you can think of it as a virtual computer whose machine code is Java bytecode. This is not a real computer, but a virtual one that can execute Java bytecode instructions.

JRE is a JVM implementation. The implementation is OS-specific (of course), but it provides an OS-independent external interface (for example, you can run the same Java code in Windows JRE and Linux JRE). Since the late 90s, this is a "one-time deal."

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http://docs.oracle.com/javase/7/docs/technotes/guides/index.html#jre-jdk

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JVM is a process launched by java.exe or javaw.exe , which exists in the bin folder of the JRE . JRE is a set of necessary binaries to run a Java process. JRE is not only OS specific, but also architecture specific.

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