Why int value must be initlize in first case mentioned below?

Question

I have two different cases where I have used boolean in if condition. Why I need to initialize variable p in CASE 1?

CASE 1:

public static void main(String[] args) {
    int p;
    if(Boolean.TRUE){
        p=100;
    }
    System.out.println(p);
}

CASE 2:

public static void main(String[] args) {
    int p;
    if(Boolean.TRUE){
        p=100;
    }
    System.out.println(p);
}

Answer 1

Simple answer from Oracle:

Local variables are slightly different; the compiler never assigns a default value to an uninitialized local variable. If you cannot initialize your local variable where it is declared, make sure to assign it a value before you attempt to use it. Accessing an uninitialized local variable will result in a compile-time error.

And although p is always initialized from the if statement, but the compiler will investigate all the cases of a wrapper Boolean. To solve it:

public static void main(String[] args) {
   int p;
   if(Boolean.TRUE){
       p=100;
   } else {
       p= 0; //for example. The compiler will see all the cases are covered
   }
   System.out.println(p);
}//no error