unable to understand some code

public class Test
{
    private final static Class<?>[] TEST_CLASSES = new Class[]{};
    private static final String DEFAULT_OS = "window";
    private static final String DEFAULT_BROWSER = "firefox";

    public static void main(String[] args)
    {
        if (args.length > 0) {
            for (int i = 0; i < args.length && args[i].split("=").length == 2; i++) {
                String key = args[i].split("=")[0];
                String value = args[i].split("=")[1];
                System.setProperty(key, value);
            }
        }
       
        System.out.println("window: " + System.getProperty("window", DEFAULT_OS));
       

        List<String> testSuites = new ArrayList<String>();

        ----
        some other code
        ----
    }

    I am not able to understand below things from above code, Please help me to understand the below

    1. Mentioned inside the for loop, (i < args.length && args[i].split("=").length == 2), what does mean "args[i].split("=").length == 2"
  
    2. String key = args[i].split("=")[0];
       String value = args[i].split("=")[1];
in 2nd point seems like array 1st and 2nd index for [0] and [1] but confusing
       
      What does mean args[i].split("=")[0]; and args[i].split("=")[1]; I am confused with [0] and [1] written in the end