CareerCup

public static void countWords(String fileName) throws IOException{
		BufferedReader br=new BufferedReader(new FileReader(fileName));
		String line=null;
		int count=0;
		while((line=br.readLine())!=null){
			count+=line.split(" ").length;
		}
		System.out.println(count);
	}

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;

public class NumberOfWordsInaFile {
	
	/*
	 * abc.txt
	 * Please dont try to make me a fool. I will enter lotz of words with blank                       spaces
	 */
	public static void main(String[] args) {
		try {
			
			InputStreamReader isr=new InputStreamReader(System.in);
			BufferedReader br1=new BufferedReader(isr);
			System.out.println("Enter the fil name :");
			String s3=br1.readLine();
			FileReader fr=new FileReader(s3);
			BufferedReader br=new BufferedReader(fr);
			String s=null;
			List<String>l=new ArrayList<String>();
			
			while((s=br.readLine())!=null){
				
				String []s2=s.split(" ");
				
				for(int i=0;i<s2.length;i++){
			      //this is to eliminate the "" present in string array after split		
					if(!(s2[i].equals(""))){
						l.add(s2[i]);
					}	
				}
			}
			
			System.out.println(l.size());
	
		} catch (Exception e) {
			
			System.out.println("Error while processing");
			
		}
		
	}

}

public void main_test() throws IOException {
		long starttime = System.nanoTime();
		FileInputStream fis = new FileInputStream("input.txt");
		try(InputStreamReader is = new InputStreamReader(fis)){
			int ch;
			int count = 0;
			while((ch = is.read()) != -1){
				if(ch == ' ' || ch == '\n')
					count++;
			}
			long endtime = System.nanoTime();
			System.out.println("count is "+(count+1)+"exec time is "+(endtime-starttime));
		}
	}

public void main_test1() throws FileNotFoundException{
		long starttime = System.nanoTime();
		try(Scanner fr = new Scanner(new File("input.txt"))){
			int count = 0;
			while(fr.hasNextLine()){
				count += fr.nextLine().split(" ").length;
			}
			long endtime = System.nanoTime();
			System.out.println("count is "+(count+1)+"exec time is "+(endtime-starttime));
		}
		
	}

outputs
count is 27543exec time is 55029484
count is 27543exec time is 124688369

junit times:
main_test: 0.048
main_test1: 0.126

decide for yourself whichone is better