Installing Java on Windows is a fundamental step for developers to set up their development environment, as it allows them to develop software applications across various platforms. To install Java on Windows, one needs to download the Java SE Development Kit (JDK) from the official Oracle website, run the installer, and follow the on-screen instructions, including adding the JDK bin directory to the system variables and verifying the installation by typing `java -version` in Command Prompt. Troubleshooting issues during installation may require administrative access, accurate path configuration, and disabling firewalls or antivirus software if necessary. Once installed and configured, Java can be used to develop and run Java-based software applications, with different versions of Java (JDK, JRE, JVM) having distinct purposes. While not mandatory, uninstalling older Java versions before installing a new one is recommended to prevent conflicts and minimize security risks, and multiple Java versions can coexist on the same system by adjusting the JAVA_HOME variable and Path accordingly. Java is free for personal and development use, but commercial users should review Oracle's licensing terms.