The Basic Law (their Constitution) of Israel defines it as a Jewish state. Its first page says:
The Land of Israel is the historical homeland of the Jewish People, in which the State of Israel was established.
(b) The State of Israel is the nation state of the Jewish People in which it realizes its natural, cultural, religious and historical right to self-determination.
(c) The realization of the right to national self- determination in the State of Israel is exclusive to the Jewish People.