Working with Environment Variables in Java

Working with environment variables in Java allows for the configuration of Java applications without explicitly storing settings in code, providing several advantages such as avoiding updates to code when settings change, preventing exposure of sensitive credentials, and enabling deployment of the same code in multiple environments. The most common way to access environment variables is through the `System.getenv()` method, which can be used to retrieve values or a default value if no matching key is found. Environment variables can also be set using various methods including setting them via the operating system's shell, command prompt or PowerShell console, and using .env files that store key-value pairs defining environment variables required for an application to work. Reading .env files can be achieved using packages such as dotenv-java or dotenv-kotlin, and it is essential to exclude sensitive data from version control when storing it in .env files.