I was given a pre-screen with two questions. Only after answering these two was a phone screen scheduled, which I have not done yet. The first was in regards to object oriented fundamentals. The question was about encapsulation. Four class definitions were presented and you were to select the class that demonstrated encapsulation. No java programmer should ever fail this. The second was a question about data structures. The question asked about the appropriate structure to use given the requirements. I felt that depending upon aspects of the requirement not stated, it could be one of two possible choices, but also felt that a specific response was suggested, thus I selected (correctly) the one seemingly most appropriate. I also replied stating that a real world answer would depend on other unstated factors. Questions about performance, IMHO, are ridiculous as rarely is the problem going to come down to the use of a particular data structure. More likely it will be because the author has poorly written his/her code, doing something stupid like reading from the db repeatedly when only one read is necessary.