java read file bufferedreader

1try {
2	File file = new File("data.txt");
3	BufferedReader reader = new BufferedReader(new FileReader(file));
4	String line;
5
6	while((line = reader.readLine()) != null) {
7	 	 System.out.println(line);
8	}
9} catch(IOException e) {
10  	e.printStackTrace();
11}

1import java.io.BufferedReader;
2//
3BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
4System.out.println(reader.readLine());

1class Main {
2	public static void main (String[] args) throws IOException{
3                      
4		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
5		String[] str = br.readLine().split(" ");      // 6 2
6		String[] input = br.readLine().split(" ");   // 1 2 3 4 5 6
7
8
9		int n = Integer.parseInt(str[0]);  // 6
10		int k = Integer.parseInt(str[1]);  // 2
11
12		
13      	int [] arr = new int [n];
14		
15      	for(int i=0; i<n; i++) 
16		{
17         arr[i] = Integer.parseInt(input[i]);  // 1 2 3 4 5 6
18        }
19	  
20	  
21	}
22}
23

1private static BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
2private static StringTokenizer st;
3static String next() throws IOException {
4    while (st==null||!st.hasMoreTokens()) {
5        st = new StringTokenizer(br.readLine().trim());
6    }
7    return st.nextToken();
8}
9static long readLong() throws IOException {
10    return Long.parseLong(next());
11}
12static int readInt() throws IOException {
13    return Integer.parseInt(next());
14}
15static double readDouble() throws IOException {
16    return Double.parseDouble(next());
17}
18static String readLine() throws IOException {
19    return br.readLine().trim();
20}