How to read multiple Integer values from a single line of input in Java?

I use it all the time on hackerrank/leetcode

    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    String  lines = br.readLine();    
        
    String[] strs = lines.trim().split("\\s+");
            
    for (int i = 0; i < strs.length; i++) {
    a[i] = Integer.parseInt(strs[i]);
    }

Try this

public static void main(String[] args) {
    Scanner in = new Scanner(System.in); 
    while (in.hasNext()) {
        if (in.hasNextInt())
            System.out.println(in.nextInt());
        else 
            in.next();
    }
}

By default, Scanner uses the delimiter pattern "\p{javaWhitespace}+" which matches at least one white space as delimiter. you don't have to do anything special.

If you want to match either whitespace(1 or more) or a comma, replace the Scanner invocation with this

Scanner in = new Scanner(System.in).useDelimiter("[,\\s+]");