Unreachable code in eclipse

What does the following mean?

Exception in thread "main" java.lang.Error: Unresolved compilation problem:
Unreachable Code    
at mycode.sample.main(sample.java:24) 

I'm hoping I can find the line where the error occurred. I thought "24" is the line, but I only have 23 lines of code in my project.

Here's the project code

package mycode;
import java.io.*;

public class sample {
  int first;
  int second;

  public sample (int fir,int sec)
  {
    fir = first;
    sec = second;
  }

  public void add()
  {
    System.out.println(first+second);       
  }

  public static void main(String[] args) throws IOException
  {
    BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
    int f = Integer.parseInt(reader.readLine());
    // int s =  Integer.parseInt(reader.r   eadLine());
    sample sample2 = new sample(f,100);
    sample2.add();
  } 
}   

I would like to understand this error message. Thanks in advance.

The first message, Exception in thread "main" java.lang.Error: Unresolved compilation problem:means your code does not compile. You need to identify the error and fix it. Modern IDEs e.g. Eclipse, Netbeans, etc flag compile errors. They can help you to quickly identify the source.

The second error:

Unreachable Code
at mycode.sample.main(sample.java:24

means that the code at line 24 will never be reached.

Here is an example of unreachable code:

public void doSomething() {
    if (true) {
        return;
    }
    // All code below here is considered unreachable code
    doSomething()
}