Recruitment process starts with a 90min Codility test. This test has 3 problems to solve. The first one can be solved with a simple quicksort algorithm for arrays that's already implemented in Java. After this they scheduled a day to come over to their offices. This day begins with 2 written tests of 45min each. The first test is about general programming logic. They'll give you 4 basic operations (set to zero, increment, loop, copy value from one variable to another) and will ask you to build new functions. Don't forget you can use all of the functions you've already built to answer the questions. The last question will ask you what a piece of code does and in my case was to find out wether a number was prime or not. The second test is about Java and they'll ask you to implement a simple linked list. There's one question about recursion. No matter how the tests go, Ocado will provide lunch for you. After that they'll let you know wether or not you've passed the tests. If you did pass the tests you'll get to see their warehouses and you'll have 2 interviews in the afternoon. The first interview will be very technical and 3 of Ocado's software engineers will ask you multiple questions about SQL and Java. They may ask you to write a small method on a white board. The second interview is more of a chat about you and your expectations.

Step 1 - Phone interview with an external recruiter Step 2 - Online assessment Java test. Three problems in 100 minutes via codility.com testing platform. Easy to medium difficulty. Step 3 - On site assessment day. Two test, 45 minutes each, one aptitude test and one standard Java test (Linked list). If you pass the morning session you will have one (or more) face-to-face interview(s) with some dev leader. Step 4 - Final fate-to-face blackboard technical interview with at least two dev leader and a manager.

I applied through a recruiter. The process took 3 weeks. First round : Codility online test : 3 programs to be completed. Very easy if you have worked on examples in Codility website. Try to get 100% results while working on examples. In test, I could complete 2 programs but could not complete the 3rd one. But they selected me for 2nd round of interview which was at their office in Hatfield. Second round : Two paper based tests in this 2nd round. 1st paper based test was on pseudo code. Some questions are fill in the blanks and some questions are write code for the function. They would have defined some inbuilt functions like (ZERO X : initialise the variable x with value 0, INCR X : initialise the value of the variable x with 1, ASSIGN (X,Y) : Assign the value of Y to X, X=Y, LOOP(X) : run the instructions written inside the loop for X times ) Questions are mainly on addition, subtraction, multiplication, division, finding the biggest number (out of 2 numbers) etc..using the predefined functions and also you can use the functions that has already defined in the previous questions. For example if 1st question is ADD(X,Y) and 2nd question is SUBT(X,Y) and 3rd question is MULT(X,Y), while solving the 3rd question you can use the function that was in first question that is ADD(X,Y). Try to be fast in solving the questions. 2nd paper based test was on Java singly linked list implementation. Some questions are fill in the blanks and some are write code for the function. If you practice the implementation of linked list in java(Insert, delete, count...) by understanding, you can clear this test. One more important thing : They do not consider combined score of the two tests. In 1st paper based test passing marks is 15 out of 20 and 2nd paper based test passing marks is 6 out of 10. So concentrate on both tests. I took lot of time in understanding 1st paper so did not solve many questions. There were 13 questions in 1st paper and around 5 questions in 2nd paper.