Why Java identifies unreachable code only in case of while loop? -

this question has answer here:

if have code like

public static void main(string args[]){     int x = 0;     while (false) { x=3; }  //will not compile   }

compiler complaint x=3 unreachable code if have code like

public static void main(string args[]){     int x = 0;     if (false) { x=3; }     for( int = 0; i< 0; i++) x = 3;    }

then compiles correctly though code inside if statement , for loop unreachable. why redundancy not detected java workflow logic ? usecase?

as described in java language specification, feature reserved "conditional compilation".

an example, described in jls, may have constant

static final boolean debug = false;

and code uses constant

if (debug) { x=3; }

the idea provide possibility change debug true false without making other changes code, not possible if above code gave compilation error.

Brent