Why is Palestine in war?

Answer 1
because it bombs Israel constantly for no reason
Palestine brought war to themselves, its their fault there was a war.

Answer 2
It depends on which Palestinian conflict the question is referring to.

Is it the Arab-Palestinian Conflict? -- which began in 1948, but became much more violent in the 1970s and 1980s, killing between 5,000-25,000 Palestinians depending on the estimates used. This conflict began when the Palestinians fled from the former Mandate of Palestine and the governments of the Arab countries to which they fled preferred to effectively incarcerate them in refugee camps for generations.

Is it the Israeli-Palestinian Conflict? -- which began in the 1920s, but became much more widespread in 1947 with the Jewish-Arab Engagement and the Arab-Israeli War of 1948-9. Approximately 19,000 Palestinians have died in the Israeli-Palestinian Conflict. This conflict started in the conflict between Zionism (Jewish Nationalism) and resurgent Arab Nationalism. It continues as a conflict between these two nationalisms and various religious, political, social, and economic groups which have chosen to support one side or the other.

Is it the Palestinian Civil War? -- which began in 2006, but most violence took place in 2007 with approximately 600-1000 deaths. The causes of this conflict deal primarily with leadership/political disputes between Fatah and Hamas over governance of the Palestinian Territories.