Why does code alternative(1) compile without warnings, and code alternative(2) produce an "unchecked cast" warning?

Common for both:

class Foo<T> {
    Foo( T [] arg ) {
    }
}

Alternative (1):

class Bar<T> extends Foo<T> {
    protected static final Object [] EMPTY_ARRAY = {};

    @SuppressWarnings("unchecked")
    Bar() {
         super( (T []) EMPTY_ARRAY );
    }
}

Alternative (2):

class Bar<T> extends Foo<T> {
    @SuppressWarnings("unchecked")
    Bar() {
         super( (T []) EMPTY_ARRAY );
    }

    protected static final Object [] EMPTY_ARRAY = {};
}

Alternative (2) produces:

javac -Xlint:unchecked Foo.java Bar.java 
Bar.java:4: warning: [unchecked] unchecked cast
             super( (T []) EMPTY_ARRAY );
                           ^
  required: T[]
  found:    Object[]
  where T is a type-variable:
    T extends Object declared in class Bar
1 warning

This is:

java version "1.7.0_07"
Java(TM) SE Runtime Environment (build 1.7.0_07-b10)
Java HotSpot(TM) 64-Bit Server VM (build 23.3-b01, mixed mode)