This means that it will not be inserted in the table of contents. Only the second line makes the Bibliography visible in the ToC. Now it comes the problem. When I click on the "Bibliography" in the ToC to use the hyperlink, the document leads me not to the page in which the bibliography starts, but in the page above the bibliography.
It is not such a problem, but still does anyone know how to fix it?
This way of bringing the bibliography into the ToC doesn't produce an anchor for hyperref. Hence it generates a false page link. You may try the tocbibind package and omit the manual insertion of the bibliography in the ToC. This is procedure for a standard document classes. Other classes may have built-in features.