Today i was doing a small pet project in Java, and seen the following paradox. The following code

import java.io.FileInputStream;
import java.io.IOException;

public class Example {
    public static boolean run() {
        try {
            FileInputStream fis = new FileInputStream("/noSuchFileExists");
            return true;
        } catch (IOException ioe) {
            System.out.println(ioe.toString());
            System.exit(1);
            return false;
        }    
    }
    
    public static void main(String[] args) {
        System.out.println(run());
    }
}

compiled correctly, even though the return false statement will never be executed, simply because System.exit(1) terminates the program. Funny isn't it? The results of an execution verified my initial suspicions.

nefarian:~ bkarak$ java Example
java.io.FileNotFoundException: /noSuchFileExists (No such file or directory)

And a decompilation of the class produced:

nefarian:~ bkarak$ javap Example -c
Compiled from "Example.java"
public class Example extends java.lang.Object{
public Example();
  Code:
   0:   aload_0
   1:   invokespecial   #1; //Method java/lang/Object."":()V
   4:   return

public static boolean run();
  Code:
   0:   new     #2; //class java/io/FileInputStream
   3:   dup
   4:   ldc     #3; //String /noSuchFileExists
   6:   invokespecial   #4; //Method java/io/FileInputStream."":(Ljava/lang/String;)V
   9:   astore_0
   10:  iconst_1
   11:  ireturn
   12:  astore_0
   13:  getstatic       #6; //Field java/lang/System.out:Ljava/io/PrintStream;
   16:  aload_0
   17:  invokevirtual   #7; //Method java/io/IOException.toString:()Ljava/lang/String;
   20:  invokevirtual   #8; //Method java/io/PrintStream.println:(Ljava/lang/String;)V
   23:  iconst_1
   24:  invokestatic    #9; //Method java/lang/System.exit:(I)V
   27:  iconst_0
   28:  ireturn
  Exception table:
   from   to  target type
     0    11    12   Class java/io/IOException


public static void main(java.lang.String[]);
  Code:
   0:   getstatic       #6; //Field java/lang/System.out:Ljava/io/PrintStream;
   3:   invokestatic    #10; //Method run:()Z
   6:   invokevirtual   #11; //Method java/io/PrintStream.println:(Z)V
   9:   return

}

This is a really funny situation. If you dont write the return false statement, the compiler will report and error.

I dont really know if the compiler should handle this situation. Of course System.exit(1) is the only direct function that kills the jvm process, and probably the compiler should be aware of it. Or it should not?