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I got RE on my code, why???

Code:
import java.io.*;
import java.util.*;

public class Main {
public static void main(String[] args) throws IOException {
BufferedReader vhod = new BufferedReader(new InputStreamReader(System.in));
int[] tab = new int[100];
int k = 0;

String line = vhod.readLine ...

I always get Runtime Error and I can't fugure it out why. Do you know why?

My code in Java:

import java.io.*;
import java.util.*;

public class Main {
public static void main(String[] args) throws IOException {
BufferedReader vhod = new BufferedReader(new InputStreamReader(System.in));

while ...