What is the difference between JDK and JRE?

The Java Development Kit (JDK) is a software development kit that contains the tools and libraries needed to develop Java applications. The JDK includes the Java Runtime Environment (JRE), which is a set of libraries and tools that allow Java applications to run on a computer.

In other words, the JRE is a subset of the JDK that includes the tools and libraries needed to run Java applications, while the JDK includes the JRE as well as additional tools and libraries for developing Java applications.

Here are some key differences between the JDK and the JRE:

• The JDK includes the JRE: As mentioned, the JRE is included in the JDK, so you don't need to install the JRE separately if you have the JDK installed.

• The JDK includes tools for developing Java applications: The JDK includes a number of tools for developing Java applications, including the javac compiler, the java interpreter, and the jar packaging tool. These tools are not included in the JRE.

• The JDK includes additional libraries: The JDK includes a number of additional libraries that are not included in the JRE, such as the tools.jar library and the sun.misc.Unsafe class.

In general, you will need to install the JDK if you want to develop Java applications, while the JRE is sufficient if you just want to run Java applications.

I hope this helps! Let me know if you have any questions.