Some Haredi Jews think that the State of Israel is not the true resurection of Israel since the Messiah has not come yet. The use of the flag and the image of the Star as symbolic of the Jews is controversial with those sects.
The Star of David or Magen David (David's Shield) is believed to have been the symbol on King David's battle shield as well as the shape on Solomon's ring (the Seal of Solomon). It is also sometimes referred to as the Jewish star. It has more of a cultural symbolism than religious. The stripes are thought to reflect the blue threads or stripes in a tallit.
It was adopted as the flag of israel on October 28, 1948, (25 Tishrei 5709) or by a vote in the Knesset on May 24, 1949.