What does .split do in java code example

Example 1: java split string

String yourString = "Hello/Test/World";
String[] strings = yourString.split("/" /*<- Regex */); 

Output:
strings = [Hello, Test, World]

Example 2: split method in java

public class SplitExample2 { 
    public static void main(String args[]) 
    { 
        String str = "My name is Chaitanya";
        //regular expression is a whitespace here 
        String[] arr = str.split(" "); 
  
        for (String s : arr) 
            System.out.println(s); 
    } 
}

Example 3: split on . in java

String textfile = "ReadMe.txt";
String filename = textfile.split("\\.")[0];
String extension = textfile.split("\\.")[1];