Input: str = “Hello, how are you ?”
Output:
Hello
how
are
you

comma(, ), white space and question mark (?) are removed and there are total 4 words in string s.
Each token is printed in the same order in which it appears in string s.

Input: “Azad is a good boy, isn’ t he ?”
Output:
Azad
is
a
good
boy
isn
t
he

Approach: 

// Java program to split all
// non-alphabetical characters
import java.util.Scanner;

public class Main {

	// Function to trim the non-alphabetical characters
	static void printwords(String str)
	{

		// eliminate leading and trailing spaces
		str = str.trim();

		// split all non-alphabetic characters
		String delims = "\\W+"; // split any non word
		String[] tokens = str.split(delims);

		// print the tokens
		for (String item : tokens) {

			System.out.println(item + " ");
		}
	}

	public static void main(String[] args)
	{

		String str = "Hello, how are you ?";
		printwords(str);
	}
}

Output:

Hello 
how 
are 
you

Time Complexity: O(N)