TCS Backend Java Developer Interview Questions and Answers

Q1. What is idempotent term in patch and put?
Ans. 
Idempotent term in patch and put means that multiple identical requests have the same effect as a single request.
• Idempotent means that the result of a successful request is the same regardless of how many times it is repeated.

• In PATCH and PUT requests, idempotent means that sending the same request multiple times will not have any additional side effects.

• For example, if a PATCH request updates a resource with specific ...read more
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Q2. Java memory types and which object stores where?
Ans. 
Java memory types and where objects are stored
• Java memory consists of stack and heap

• Primitive data types are stored in stack

• Objects and arrays are stored in heap

• References to objects are stored in stack

• Example: int num = 5; // num is stored in stack, value 5 is stored in stack

• Example: String str = new String(); // str reference is stored in stack, actual String object is stored in heap
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Q3. Hash map store unique name?
Ans. 
Yes, hash map stores unique keys.
• Hash map in Java does not allow duplicate keys. If you try to insert a duplicate key, it will replace the existing value with the new one.

• However, hash map allows duplicate values.

• Example: HashMap<String, Integer> map = new HashMap<>(); map.put("John", 25); map.put("Jane", 30); map.put("John", 35); // 'John' key will now have value 35.
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Q4. Hashmap java 7 and java 8 difference?
Ans. 
Java 8 introduced new methods for HashMap such as forEach, compute, merge, etc.
• Java 8 introduced new methods like forEach, compute, merge for HashMap operations

• Java 8 allows using lambda expressions for iterating over HashMap entries

• Java 8 introduced default methods in Map interface for HashMap
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Q5. Can we create static method or variable inside static main()
Ans. 
No, static methods or variables cannot be created inside static main() method.
• Static methods or variables cannot be created inside another static method.

• Static methods or variables can only be created at the class level, outside of any method.

• Example: public class MyClass { static int myVariable = 10; }
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Q1. Springboot questions
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Q2. Rest controller and spring security basic questions
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Basic aptitude question, you can follow Study Smart Youtube channel. Some question you will get same

Q1. Depends what language you have written in your resume. For Java you will definately asked oops concept
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Q2. OOPs concept, with some real life examples. Basic programming like the Fibonacci series, reverse a string such like question
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Q1. Intro, Simple puzzle type question. about family and yourself.
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