Fragen aus Vorstellungsgesprächen für data engineer, von Bewerbern geteilt
If you take 3 subsequent number (n, n+1, n+2) and know, that n and n+2 are prime numbers, can you proove, that n+1 is always dividable by 6?
1. if n and n+2 are prime, the n+1 is dividable by 2; 2.one of the three subsequent number (n, n+1, n+2) must be dividable by 3. because n and n+2 are prime, then n+1 is dividable by 3. So n+1 is dividable by 6.
3, 4, 5. 3 and 5 are prime. 4 is not divisible by 6.
n+1 will be divisible by 2 since n and n+2 are prime now n,n+1 or n+2 any one of them should be divisible by 3 n and n+2 are prime so n+1 should be divisible by 3 Hence proved
The first round you will asked the following question. 1. Explain about the tera sort that happens between the map and reduce phase in hadoop job. 2. Explain about class loader, can you have more than one class loader in jvm. 3. Explain how indexing in implemented in sql databases, be prepared to take about b-tree and tree balancing algorithm. 4. How does java guarantee the hashmap look up in O(1). Round 2 1. You will asked to write java streaming code to parse infinite input while keeping memory low the output should predefined length of random sample.