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Oracle Interview Gandhinagar

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Updated: 2026-09-24

This note records a three round Oracle interview in Gandhinagar, Gujarat, rated 8 out of 10 for difficulty. Two rounds happened on the same day and the third followed the next week. Round one mixes a socks puzzle, word reversal, a sliding window substring problem, a handshake count, and two SQL salary queries. Round two turns to Java, covering method overriding, multi-threading with ExecutorService, and a concurrent ATM design. Round three adds date arithmetic without libraries, a longest common prefix problem, a zig-zag matrix traversal, and a table tennis puzzle. Each round notes its duration and difficulty, and the closing section lists preparation advice.

Location: Gandhinagar, Gujarat, India
Overview: 3 interview rounds (2 rounds on the same day, 1 the following week)
Overall difficulty: 8/10

Round 1 - General Knowledge

  • Duration: 60-75 minutes
  • Date: 9/5
  • Difficulty: 7.5/10
  • Content:
    • Logic puzzle: Arrange 4 pairs of socks with different distances between the two socks of the same color
    • Java - Reverse words: Keep the positions of the spaces unchanged
      • Input: "Hello Param How are You Welcome to oracle"
      • Output: "olleh maraP woH era uoY emocleW ot elcaro"
    • Java - Sliding Window: Find the longest substring without repeating characters
      • Input: "abcdba" → Output: "abcd"
    • Math: Compute the number of handshakes among N people
      • Formula: n * (n - 1) / 2
    • SQL: Find the department with the second-highest salary (3 tables: Employee, Department, Salary)
    • Advanced SQL: Find the second-highest salary without window functions, limit, or offset

Round 2 - Java & System Design

  • Duration: 60 minutes
  • Date: 9/5
  • Difficulty: 8/10
  • Content:
    • Java OOP: Method overriding and its real-world uses
      • Examples of inheritance, abstraction, encapsulation, polymorphism
    • Multi-threading & ExecutorService: Design an ATM system
      • Support multiple users withdrawing concurrently
      • Ensure synchronization
      • Check the balance before withdrawing
    • String processing: Find the greatest distance between two occurrences of a repeated word
      • Input: A string in which the word "Param" appears multiple times
      • Based on the first and last index of the word

Round 3 - Algorithms & Advanced String Processing

  • Duration: 1 hour
  • Date: 11/5 (Monday)
  • Difficulty: 8.5/10
  • Content:
    • Date handling: Add days without using Java libraries
      • Input: "09-May-2025", n = 30 → Output: "08-Jun-2025"
      • Handle it yourself: days per month, leap years, converting string → date
    • String: Find the longest common prefix
      • Input: ["automatic", "auto", "autonomous"] → Output: "auto"
    • Matrix traversal: Traverse a matrix in a "zig-zag + return" pattern
      • 4x4 matrix, traverse from [0,0] in the pattern, then come back along the last row and first column
      • Output: 1, 2, 6, 7, 11, 12, 16, 15, 14, 13, 9, 5
    • Logic puzzle: Find the winner of a table tennis match
      • 3 players, the winner keeps playing
      • Based on the number of matches and the last consecutive winner (Player 2 won 7 matches)

Summary

Strengths

  • Varied questions: logic, algorithms, string processing, dates, multi-threaded systems
  • Friendly interviewers who are open to sharing
  • Highly academic, thought-provoking

Preparation Advice

  • Review core Java (basic and advanced)
  • Practice string-processing problems and puzzles
  • Get familiar with multi-threading & ExecutorService
  • Train your logical thinking and your ability to explain clearly

See also: Amazon SDE Interview · Fresher Java Interview · Coding Interview Resources