Understanding the Differences Between Java JDK, JRE, and JVM

Anyone who had even a vague experience with Java programming language offers a different level of complexity. It comprises multiple components; it is the trio of JDK, JRE, and JVM that form this language’s core. Though these concepts may all seem alike, the fact remains that are vastly different from each of them serving a particular purpose in the larger picture that is programming with Java. Let’s discuss these concepts and also explore the differences between them.

1. JDK

Java Development Kit, or simply JDK, is a crucial facet of Java. It delivers all the tools along with executables and binaries requisite for compiling, debugging, and executing a Java program. Also called a superset of Java Runtime Environment (JRE), a loader/interpreter, JDK also includes javac, a compiler; Javadoc, a document generator; and jar, an archiver among other tools developers need in this context. We must note that JDK is a platform-specific software, which is why it has different installers for Mac, Unix, and Windows systems.

2. JRE

Java Runtime Environment, a.k.a. JRE or Java RTE provides the runtime environment. It includes Java Virtual Machine (JVM), core classes, and supporting files to execute a program successfully. Though remember that to execute any Java app, one must have JRE installed on the machine since it is the basic requirement for executing Java applications on any machine.

You can either download JREs as part of JDKs or you can download them individually. Also, JREs are platform-dependent — what that means that you must select the JRE bundle to import and install by the type of machine, i.e. its OS and architecture.

3. JVM

Java Virtual Machine (JVM) provides the runtime environment needed for executing Java bytecode. Referred to as virtual because it delivers a machine interface independent of the fundamental operating system as well as the machine hardware architecture. This freedom from both hardware and the OS is a fundamental principle of the write-once-run-anywhere merit of Java programs.

JVM enables model performance for Java apps by leveraging various progressive techniques, integrating a contemporary memory model, adaptive optimizer, and garbage collector.
JDK vs. JRE vs. JVM: A quick summary

The following can be used to summarize the relationship between JDK, JRE, and JRM.

1. JRE is the union of JVM and libraries to run a Java application.
2. JDK is a combination of JRE and other tools required for developing a Java application.

To further help you understand the differences, we’ll end with this: JDK is meant for development, whereas JRE is for running Java programs. Also remember, both JDK and JRE contain JVM to allow developers to run their Java programs. Therefore, JVM is the nucleus of Java and enables platform independence.

So, when you go looking for certified Java developers for hire, make sure that they not only know but fully understand these important concepts so you can be sure that your Java applet or app is of the highest quality.