How does Christianity deal with biblical criticism related to the Old Testament? As an orthodox Jew I have seen quite a stir lately regarding the topic of biblical criticism, specifically towards the Old Testament (Torah). 

I have perused several questions in this stack which seem to address this topic in general, and learned a lot about apologetics, but I have not seen answers that address some of the major claims of biblical criticism, especially as it pertains to the Old Testament. 

For example:


The story of Noah and the flood seems to be contradicted by archaeological evidence as well as having been 'borrowed' from earlier flood narratives such as the Gilgamesh story
Many of the portions of the Old Testament seem to be borrowed from earlier near eastern texts such as the Hammurabi code 
The notion that there are multiple authors (documentary hypothesis) of the Old Testament.


In short, how does Christianity deal with some of the major contentions of biblical criticism towards the Old Testament?



I apologize if any parts of my question offend any sensibilities to which I am unaware.
Christians are very diverse on how they handle this type of criticism. Probably the most visible school of thought in today's media are the literalists. These Christians accept that the Bible was fully authored by God and is complete and infallible. For them, Gilgamesh is either fiction or a pagan account of the Genesis story. Hammurabi's code is a set of inferior pagan laws.

The most liberal Christians treat the Bible as one of many worthwhile ancient writings and as a product of the sharing of knowledge across cultures. The Genesis account was inspired by Gilgamesh. Mosaic Law and Hammurabi's Code may have been derived from the same source.

Most Christians fall somewhere in between the two. The Bible wasn't written in a vacuum and it's just a matter of course that there are similarities to other writings from other cultures. It doesn't change the Bible's supremacy and it doesn't impact their faith. An explanation I heard from a conservative reform Jew fits nicely. God spoke to lots of people. The Jews were just the ones who heard and obeyed.

That there were multiple authors of the Bible is just a given. Even the most conservative literalists believe that God used many people to write His word. Different groups might disagree on how many authors there were, but there was definitely more than one.