I get that, but they set up a state in an existing country. That's why the Arabs invaded.
No they didn't. There was no country called Palestine and no one invaded it. This is a complete falsehood put about by people who simply don't know the history. The last time there was a state called that, it was a Jewish ruled, Roman province, until the revolt in 79AD when most Jews were killed or exiled (although some remained).
The territory was then part of various empires until it passed to the control of the Ottoman Empire in 1516. It was 400 years later that the British defeated the Turks to occupy the place. The history since then is a fairly dismal one, with various vested interests, both colonial (French and British) and Arab all trying to establish control.
I'd highly recommend the book 'A Line In The Sand' for a detailed description of that period, when the Middle East was cynically carved up with lots of new countries created (including Jordan, Iraq & Syria) and given to various tribal chiefs as a reward for their support. Great Britain was left with a mandate for the territory that now comprises Israel, the West Bank & Gaza but couldn't get agreement on what to do with it.
Eventually they gave up the Mandate granted by the League of Nations in 1923 and handed to problem back to the newly-formed United Nations. That was after an Anglo-American Commission made recommendations that both the UK and USA said they'd accept, but then reneged on that pledge when they didn't like various parts of the recommendations.
The UN voted on the partition plan, which gave far less to Israel, and far more to the Arabs, than they eventually got. The Israelis decared independence (tomorrow is the 73rd anniversary incidentally) and a number of Arab armies went to war against the new state. The thing was, the plan if they won wasn't to give it back to the Arab residents, as a sovereign state. Syria saw it as part of their country (a Greater Syria), as did the Egyptians.
The pre-1967 borders were established after the War of Independence and stayed that way until 1967. In those 19 years, Jordan annexed the West Bank rather than establish an independent state, while the Egyptians retained military control over Gaza. Both could have been part of a Palestinian state if they'd wanted that but those Arab countries didn't want that. They could have absorbed the refugees into the various Arab states, bt they were the ones who actually forst practiced apartheid against Palestinians, treating them very much as second-class citizens and denying them rights, while keeping them in squalid refugee camps.
In 1967 the Russians completely misled their Arab clients about Israel's intentions, lying to them about a build-up of forces that was simply false. So the Arabs mobilised but Israel, feeling threatened, struck first and ended up occupying the Golan Heights, West Bank and Gaza. And that's when it all went downhill. In 1970, Jordan struck against the Palestinians in their country, in what became known as Black September, killing thousands of them. Following the war in 1973, peace was established between Egypt, Jordan and Israel and another opportunity was missed to solve the problem of the Palestinians once and for all.
And since then, as the Israelis have expanded settlements, the Iranians have established their proxy armies Hezbollah and Hamas, and both sides' leaderships have got more extreme and belligerent.
Now go away and read some history then come back when you want to have an adult discussion based on facts. Until then stop peddling myths and fairy tales.