Java JDK (Java Development Kit) is a software development environment used for building and running Java applications. It includes a set of tools and libraries necessary for Java development, such as the Java compiler (javac), runtime environment (JRE), and various utilities.

The Java JDK provides everything you need to develop Java applications, including the Java Development Kit itself, documentation, and additional libraries. It allows you to write, compile, and run Java code on your computer. The JDK also includes the Java Runtime Environment (JRE), which is necessary to run Java applications.

To get started with Java development using JDK, you need to follow these steps:

1. Download the JDK: Visit the official Oracle website or OpenJDK website and download the JDK distribution for your operating system. Make sure to choose the appropriate version (e.g., JDK 8, JDK 11, JDK 17) based on your requirements.

2. Install the JDK: Run the installer and follow the instructions provided to install the JDK on your system. During the installation, you may need to specify the installation directory and configure environment variables.

3. Set up environment variables: After installing the JDK, you need to set up the necessary environment variables. For example, on Windows, you need to set the JAVA_HOME variable to the JDK installation directory and add the JDK’s bin directory to the system’s PATH variable.

4. Verify the installation: Open a terminal or command prompt and type java -version to verify that the JDK is installed correctly. It should display the installed Java version.

Once you have the JDK set up, you can use a text editor or an Integrated Development Environment (IDE) like Eclipse, IntelliJ IDEA, or NetBeans to write your Java code. After writing the code, you can compile it using the javac command and run it using the java command.

Note that starting from Java 11, Oracle has changed its distribution and licensing model. They now provide long-term support (LTS) releases and non-LTS releases. OpenJDK, an open-source implementation of the JDK, is also available and widely used.

It’s recommended to refer to the official documentation and resources provided by Oracle or OpenJDK for more detailed information and instructions on using the Java JDK.