This is Guava Fruit. At the farmer market that I went every morning, there is a family who always sell this fruit. I bought Guava fruit every morning. I figured I don’t get to eat much in the US then I better eat it as much as I can while I was in Thailand.
I sometime made Guava juice too. I have a recipe. You can check it out at http://www.gretchenspantry.com/recipe/guava-juice.aspx.
Here the website if you want to learn more about Guava http://en.wikipedia.org/wiki/Guava.