It is unclear what "all this hostility" refers to. Contrary to what many Arab and Muslim commentators may say, the Israeli-Palestinian Conflict really only affects the Israelis and Palestinians and had marginal to reasonably important effects on the Arab countries directly bordering Israel or Palestine. However, the Israeli-Palestinian Conflict does not cause the majority of problems or conflicts in the Middle East and is actually quite insignificant. (Such conflicts include the Turko-Cypriot War, the current Syrian Civil War, Saudi Repression of Women and Minorities, the Iran-Iraq War, the Persian Gulf War of 1990-1991, the Iraq War and the Insurgency, the Anfal Campaign and other Genocides in Iraq prior to Saddam Hussein's overthrow, the Iranian-Israeli Proxy Wars, the Cultural and Political Repression of the Kurds, South Sudanese, Darfurians, Amazigh, Pied Noirs, Jews and Christians, and numerous other conflicts).
As for the issues between Israelis and Palestinians currently, most of them have to do with the current Israeli and Palestinian governments not being interested in pursuing bilateral negotiations because of mutual distrust. Netanyahu, Israel's Prime Minister, is angered by Hamas' bellicose nature along the Israeli border and does not believe that Mahmoud Abbas is truly interested in a negotiated solution since he went to the UN to acquire statehood without a formal peace agreement. Abbas, the Palestinian Authority Chairman, is bothered by increased Israeli settlement construction and a failure on the Israeli government's part to reward his positive management of the West Bank with increased autonomy and land-area.
As for the general issues, please see the Related Questions below.
There is no such word as "piskapaians". Did you mean "Palestinians"?
no and it never will be.
Jews and Palestinians.
The facile answer would be 'Almost Continuous'.
Israel is the homeland of the Jews, and Palestine is the homeland of the Palestinians. (However, there are people on both sides who disagree with this statement.)
I am pretty sure it is Jerusalem
Jews do not think this. Most Israeli Jews support a two-state solution. They just want the Palestinians to recognize Israel's right to exist.
The Palestinians claimed that the Jews stole their land, therefore there has been unrest in that area ever since the Jews came back from Jerusalem.
Jews and Palestinians.
The "clear" hypothesis in the question is debatable at best. There have been numerous genetic and historic studies which have proven conclusively that Jews (even from Europe) are of Semitic origin as opposed to European origin. Most genetic studies show closer relations between Arab Palestinians and European Jews than those between Arab Palestinians and Middle Eastern Jews.
It depends which "Conflict in Israel" the question is asking about. If it is asking about the Israeli-Palestinian Conflict, the conflict is, strictly speaking, between Israelis and Palestinians which are national groups, not religious groups. However, the majority of Israelis are Jewish and the majority of Palestinians are Muslim. (However, there are numerous Muslim Israelis, Druze Israelis, and there are both Christian Israelis and Christian Palestinians.) If it is asking about Israel's internal political conflicts, they are often between Secular Jews and Religious Jews.
The dominant conflict in Palestine is between Israelis (who are predominantly Jewish) and Palestinians (who are predominantly Muslim), but the conflict is a political one, not a religious one.