Strange behavior with array initialization in Java?

Question

Java

I have come across some very strange behavior in Java .
According to the Java specification, when an array is created, its elements must be initialized with default values. For elements of type byte , the default value is 0 .
Consider the code on which I was able to reproduce the strange behavior:

package javatest;

import java.io.*;

public class JavaTest 
{   
    public static void main(String[] args) throws IOException
    {
        byte[] buf = new byte[5];
        
        System.in.read(buf);
        
        for (int i = 0; i < buf.length; ++i)
        {
            System.out.println((char)buf[i]);
        }
    }
}

Strange behavior begins with the following sequence of actions:
1) Enter 1 , poke Enter , the program correctly displays 1 and ends;
2) Run the program again (I run it from NetBeans IDE ), type 12345 , hit Enter , the program displays 12345 correctly and exits;
3) Run the program again, enter 123456 , poke Enter , the program displays garbage and ends;
4) The next few launches of the program with the input of any data lead to the fact that garbage is displayed - in some cases not everything is displayed, in others - what was not entered.

Maybe I don't understand something? It seems to me that this should not be.