Question

shouldn´t one pass an object to equal?

    String hej = pets.getBark();
    if(hej.equals("woff"))

why are you able to pass a string woff?

Answer 1

Under the hood, a string literal ( text inside quotes ) automatically is replaced by String instance. ( a string literal is shorthand for new String )

That is why this code works: String hello = "hello";

So,

 String hej = pets.getBark();
 if( hej.equals( new String("woff") ) ) {}

is identical to the code you provided.