在BufferedReader.read之后，Java抛出NumberFormatException错误

Question

I am trying to write a simple program. I am trying to get two user input, first one is of type char and second one is of type integer. I am using BufferedReader for taking user input. However after taking char input from user when I am pressing enter it is throwing below error.

Please enter your sex: m
Please enter your code: Please enter your salary: Exception in thread "main" jav
a.lang.NumberFormatException: For input string: ""
        at java.lang.NumberFormatException.forInputString(Unknown Source)
        at java.lang.Integer.parseInt(Unknown Source)
        at java.lang.Integer.parseInt(Unknown Source)
        at classtest.main(classtest.java:24)

To my surprise if I am taking integer input first and then char then it is not giving any error. however if I am taking char input first and then integer then it is giving error. As soon as I am pressing enter key it is throwing error. It is not even asking for second input. It is considering the input as "".

Here is my code.

import java.io.*;
import java.util.*;
public class classtest 
{ 

public static void main(String[] args) throws IOException
{           
BufferedReader br =new BufferedReader(new InputStreamReader(System.in));
int empcode;

char sex;

System.out.print("Please enter your sex: ");                        
sex=(char)System.in.read();

System.out.print("Please enter your code: ");       
empcode=Integer.parseInt(br.readLine());        
System.out.print("Code: " +empcode);         
System.out.print("Sex: " + sex);            
}
}

Answer 1

You should use br.readLine() to get the sex, and use String.charAt(0) to get the first character of it (with appropriate checking, of course):

sex = '?';
while (sex != 'M' && sex != 'F') {
  System.out.print("Please enter your sex: ");
  String line = br.readLine();
  if (line.length() == 1) {
    sex = line.charAt(0);
  }
}

Currently, your call to br.readLine() is reading the contents of System.in from immediately after the single-character sex up to the newline following it. I guess you are entering something like F\\n - so br.readLine is reading the empty string between F and the \\n exclusively.