Need help writing a code for this program

Question

Design a code that reads a sentence and prints each individual word on a different line

Answer 1

tsith's suggestion is excellent. Run it and see what happens. I just did that myself and doing so I learned something new about the Scanner class.
Before you run it, add a couple of extra System.out.println for (hopefully) illustrating debugging purposes:
import java.lang.String;
import java.util.Scanner;
public class Sentence {
    // main line of program
    public static void main(String[] args) {
        boolean z;
        String a;
        Scanner keyboard = new Scanner(System.in);
        System.out.print("Enter sentence: ");
        z = keyboard.hasNext();
        while (z) {
            System.out.println("z = " + z + ". Fetching the next word...");
            a = keyboard.next();
            System.out.println(a);
        System.out.println("Done!");
}Let us know if the program ever prints "Done!" to the console. While you are waiting, read what the javadocs has to say about the Scanner class, and pay extra attention to what it says about the hasNext() and next() methods:
http://java.sun.com/j2se/1.5.0/docs/api/java/util/Scanner.html