why does the catch block give an error with variable not initialized in Java

Question

This is the code that I\'ve written.

int num;
try {
    num=100;
    DoSomething();
    System.out.println(num);
} catch(Exception e) {
    DoSomething1();
}         


        

Answer 1

Exception handling can confuse the compiler. In this case, you know that an exception cannot possibly be thrown BEFORE the variable num is set, but the compiler doesn't know this.

The compiler thinks that an exception might be thrown before num has been set in which case num would not have been initialized when you try to print it outside the try-catch block.