java - Parameter scope vs local variable scope? -

i reading ap cs book , talked 3 types of variables:

•instance variables

•local variables

•parameters

instance variables visible throughout class etc... parameters usable within method , local variables . . .

therefore question why classify parameters , local variables different categories of variables if contain same scope. . . despite different uses of them.

because don't have same scope.

take case:

// garbage code public void dosomething(int foo) {     int meh = 0;     while (true) {          // can access foo , meh          int blah = meh++;          if (blah == foo) {              break;          }     }     // won't compile, can't access blah anymore     system.out.println(blah);     // compile     system.out.println(foo);     // compile     system.out.println(meh); }