Why can I throw null in Java? [duplicate]

Answer 1

Thinking about it this way makes it a bit more obvious as to why this works:

try {
    Exception foo = null;
    if(false) {
        foo = new FileNotFoundException();
    } // Oops, forgot to set foo for the true case..
    throw foo;
} catch (Exception e){
    System.out.println(e instanceof NullPointerException);
    System.out.println(e instanceof FileNotFoundException);
}