Oracle Interview Questions, Process, and Tips

Implement table tennis scorer

Q1. Java 8, Spring questions
Add your answer

Q1. Design questions
Add your answer

Q1. Salary discussion
Add your answer

Q1. Singleton Pattern in details
Ans. 
Singleton pattern ensures a class has only one instance and provides a global point of access to it.
• Ensures a class has only one instance by providing a global access point to it.

• Uses a private constructor to restrict instantiation of the class.

• Provides a static method to access the singleton instance.

• Commonly used in scenarios where only one instance of a class is needed, such as database connections or logging.

• Exampl...read more
Answered by AI
Add your answer
Q2. Difference between POJO and Bean
Ans. 
POJO is a Plain Old Java Object with private fields and public getters/setters, while a Bean is a Java class with private fields and public zero-argument constructors.
• POJO stands for Plain Old Java Object

• POJO has private fields and public getters/setters

• Bean is a Java class with private fields and public zero-argument constructors

• Beans are usually used in Java EE frameworks like Spring for dependency injection
Answered by AI
Add your answer
Q3. Product of an array except self
Ans. 
Calculate the product of all elements in an array except for the element itself.
• Iterate through the array and calculate the product of all elements except the current element.

• Use two separate arrays to store the product of elements to the left and right of the current element.

• Multiply the corresponding elements from the left and right arrays to get the final result.
Answered by AI
Add your answer

Q1. String a = "Something" String b = new String("Something") How many object created?
Ans. 
Two objects created - one in the string pool and one in the heap.
• String 'a' is created in the string pool, while String 'b' is created in the heap.

• String pool is a special area in the heap memory where strings are stored to increase reusability and save memory.

• Using 'new' keyword always creates a new object in the heap, even if the content is the same as an existing string in the pool.
Answered by AI
Add your answer
Q2. Predict Output based on whether static variables can be accessed from non-static method
Ans. 
Static variables can be accessed from non-static methods using an object reference or by making the variable non-static.
• Static variables can be accessed from non-static methods by creating an object of the class containing the static variable.

• Alternatively, the static variable can be made non-static to be accessed directly from a non-static method.

• Attempting to access a static variable directly from a non-static method
Answered by AI
View 2 more answers
Q3. Java 8 Features
Add your answer

Q1. Write code to emulate Producer/Consumer Problem
Ans. 
Emulate Producer/Consumer Problem using code
• Create a shared buffer between producer and consumer

• Use synchronization mechanisms like mutex or semaphore to control access to the buffer

• Implement producer and consumer functions to add and remove items from the buffer respectively
Answered by AI
Add your answer
Q2. Write code to create a deadlock
Ans. 
Creating a deadlock involves two or more threads waiting for each other to release a resource they need.
• Create two threads, each trying to lock two resources in a different order

• Ensure that one thread locks resource A first and then tries to lock resource B, while the other thread locks resource B first and then tries to lock resource A

• This will result in a situation where each thread is waiting for the other to releas
Answered by AI
Add your answer
Q3. Write code to implement LRU Cache
Ans. 
Implement LRU Cache using a data structure like LinkedHashMap in Java
• Use LinkedHashMap to maintain insertion order

• Override removeEldestEntry method to limit cache size

• Update the access order on get and put operations
Answered by AI
Add your answer
Q4. Write code two merge and remove duplicates from two sorted arrays with any Collections
Ans. 
Merge and remove duplicates from two sorted arrays without using Collections
• Use two pointers to iterate through both arrays simultaneously

• Compare elements at each pointer and add the smaller one to the result array

• Skip duplicates by checking if the current element is equal to the previous element
Answered by AI
Add your answer
Q5. Questions related to Java Commands used to start a java program (mvn related)
Add your answer
Q6. Java Memory Model
Add your answer
Q7. Write code to start 5 threads
Ans. 
Code to start 5 threads in Java
• Create a class that implements the Runnable interface

• Instantiate 5 objects of the class

• Create 5 threads using the objects and start them
Answered by AI
Add your answer
Q8. String a = "Something" a.concat(" New") What will be garbage collected?
Ans. 
Only the original string 'Something' will be garbage collected.
• The concat method in Java does not modify the original string, but instead returns a new string with the concatenated value.

• In this case, 'a' remains as 'Something' and a new string 'Something New' is created, but not assigned to any variable.

• Since the new string is not stored in any variable, it will not be garbage collected.
Answered by AI
Add your answer
Q9. Write code to read a file
Ans. 
Code to read a file in Java
• Use FileReader and BufferedReader classes to read the file

• Handle exceptions using try-catch blocks

• Close the file after reading using close() method
Answered by AI
Add your answer

Diameter of the given tree

Q1. Given a situation and asked a query
Add your answer
Q2. Longest increasing subsequence code
Ans. 
Find the longest increasing subsequence in an array
• Use dynamic programming to solve this problem efficiently

• Iterate through the array and keep track of the longest increasing subsequence ending at each index

• The final answer will be the maximum value in the longest increasing subsequence array
Answered by AI
Add your answer

Q1. What were the challenges faced during your project work,
Ans. 
The challenges faced during my project work included tight deadlines, communication issues, and technical difficulties.
• Tight deadlines required efficient time management and prioritization of tasks

• Communication issues with team members led to misunderstandings and delays in progress

• Technical difficulties such as software bugs or hardware malfunctions required troubleshooting and problem-solving skills
Answered by AI
Add your answer
Q2. Why did you choose oracle?
Ans. 
I chose Oracle for its reputation as a leader in database technology and its wide range of products and services.
• Oracle is known for its reliable and secure database solutions

• Oracle offers a variety of products and services for different business needs

• Oracle has a strong reputation in the industry for innovation and customer support
Answered by AI
Add your answer

Easy 1 dsa and 35 mcqs

Q1. All oops concepts in detail
Ans. 
Object-oriented programming concepts like inheritance, encapsulation, polymorphism, and abstraction.
• Inheritance: Allows a class to inherit properties and behavior from another class.

• Encapsulation: Bundling data and methods that operate on the data into a single unit.

• Polymorphism: Ability to present the same interface for different data types.

• Abstraction: Hiding the complex implementation details and showing only the ne
Answered by AI
Add your answer
Q2. Linked list implementation and some questions
Add your answer

Question on DSA and few puzzles and system design questions

Q1. Asked to explain and code my college project
Add your answer

Q1. Diff between right and left join
Ans. 
Right join includes all records from the right table and matching records from the left table, while left join includes all records from the left table and matching records from the right table.
• Right join keeps all records from the right table, even if there are no matches in the left table.

• Left join keeps all records from the left table, even if there are no matches in the right table.

• Example: In a right join between ...read more
Answered by AI
Add your answer
Q2. What is cursor? Why we use?
Ans. 
A cursor is a database object used to retrieve data from a result set one row at a time.
• Used to fetch and manipulate data row by row

• Improves performance by reducing memory usage

• Can be static, dynamic, forward-only, etc.

• Examples: FETCH, OPEN, CLOSE
Answered by AI
Add your answer

Q1. Right example for right join
Ans. 
A right join returns all records from the right table and the matched records from the left table.
• Use when you want to include all records from the right table, even if there are no matches in the left table.

• Syntax: SELECT * FROM table1 RIGHT JOIN table2 ON table1.column = table2.column;

• Example: SELECT * FROM employees RIGHT JOIN departments ON employees.department_id = departments.department_id;
Answered by AI
Add your answer
Q2. How to find 2nd max salary
Ans. 
To find the 2nd max salary, you can use a SQL query with the MAX() function and a subquery.
• Use a subquery to select the maximum salary excluding the highest salary.

• Order the salaries in descending order and select the second row using LIMIT and OFFSET.

• Example: SELECT MAX(salary) FROM employees WHERE salary < (SELECT MAX(salary) FROM employees);
Answered by AI
Add your answer

Q1. Salary discussion
Add your answer
Q2. Doubts about related to onboarding process
Add your answer