How do I programmatically determine operating system in Java?

To programmatically determine the operating system in Java, you can use the System.getProperty method and pass it the "os.name" property. This will return a string that contains the name of the operating system.

For example:

String osName = System.getProperty("os.name");
System.out.println(osName);

This will print the name of the operating system to the console.

You can then use this string to determine the operating system. For example:

if (osName.startsWith("Windows")) {
  // do something specific to Windows
} else if (osName.startsWith("Mac")) {
  // do something specific to Mac
} else if (osName.startsWith("Linux")) {
  // do something specific to Linux
}

Note that the string returned by System.getProperty("os.name") may contain additional information about the version and architecture of the operating system. For example, on Windows it may return a string like "Windows 10" or "Windows 7". On Mac it may return a string like "Mac OS X" or "Mac OS X 10.15". You may need to parse this string to get specific information about the operating system.