Recently interviewed with Ciena for the SDE-1(Java Developer) role (Gurgaon). Sharing my Technical Round 1 experience.

🔹 Round 1: Technical Interview

The round was a mix of DSA + Java + Spring Boot + SQL + System concepts. But was more focused on java and springboot.

🧠 DSA Questions

1. Longest Substring Without Repeating Characters

Example: abcac → abc → Output: 3

2. Merge Two Sorted Linked Lists

l1: 1 → 3 → 5  
l2: 2 → 4 → 6  

☕ Java + Spring Boot

Questions asked:

• Difference between @RestController vs @Controller
• Create a sample API
• Common Spring Boot annotations and how springboot application starts (he was expecting to mention all the annotations)

🗄️ SQL Questions

1. Find second highest salary

2. A follow up question, find second highest unique salary

3. Flip binary values

Table: BINARY_TABLE
0
1
0

Solution:

UPDATE BINARY_TABLE
SET Binary_Column = 1 - Binary_Column;

⚙️ Core Java Concepts

• Java 8 features (Streams, Collections)
• How HashMap works internally

📡 Kafka & System Concepts

• Kafka basics
• Partitions and consumers
• Handling high traffic scenarios