According to Book, Calling An instance method or variable from Static Method is not Legal. I understood, that without the reference variable it would not be possible, but with object reference it is possible
I agree! Especially because on the previous page in the section Static vs. Instance this case is illustrated with an example: it's suggested to invoke new Static().third(); from the (static) main method.
So both the columns Legal? and How? should be updated to Yes and Using a reference variable respectively.
I've noted this in the errata. I feel like this is worse than a typo/error in the book. I wanted to convey that assuming you have no reference variables, you can call a static method from an instance method but not vice versa. And that's not what the table actually conveys.