Wissen Technology Interview Questions, Process, and Tips

There is a hacker rank test for 60 minutes Link provided by the time of 1st round live screen share with hr taking screenshot for govt id proof.
Test has a 8 question in that 5 are mcqs and 2 are coding and 1 is SQL query.

Q1. F2F interview was there. Basic of Multithreading in java. Split array into chunks of given size. Class level and Object level synchronization. Given a nested array and make it into flatten array. {{1}, 2...read more
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Q1. After this we have a 3rd F2F round- What is Multithreading in java?
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Q2. Convert String camel case to snake case.
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Converts a camel case string to snake case.
• Split the string by uppercase letters

• Convert each word to lowercase

• Join the words with underscores
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Q3. Write a Java program using multithreading to print below output: n=10 Thread-1 : 1 Thread-2 : 2 Thread-3 : 3 Thread-1 : 4 Thread-2 : 6 . . Thread-1 : 10
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A Java program using multithreading to print numbers from 1 to 10 in a specific pattern.
• Create three threads and assign them to print numbers in a specific pattern

• Use synchronization to ensure the correct order of printing

• Use a loop to iterate from 1 to 10 and assign the numbers to the threads

• Print the thread name and the assigned number in the desired format
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Q4. Suggestion on best way for Java collection to store csv data. and if needed any operation on how to do? there are millions of data need to store in java collection. and some validations on this.
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Q5. How to detect a loop into LinkedList?
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To detect a loop in a LinkedList, we can use the Floyd's cycle-finding algorithm.
• Initialize two pointers, slow and fast, both pointing to the head of the LinkedList.

• Move slow pointer by one step and fast pointer by two steps at a time.

• If there is a loop, the slow and fast pointers will eventually meet.

• If either of the pointers reaches the end of the LinkedList, there is no loop.
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Q6. Difference between Callable and Runnable Class?
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Callable and Runnable are interfaces in Java used for concurrent programming. Callable returns a result and can throw an exception, while Runnable does not return a result or throw an exception.
• Callable is a generic interface with a method called 'call()', while Runnable is a functional interface with a method called 'run()'.

• Callable can return a result using the 'Future' interface, while Runnable cannot.

• Callable can t...read more
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Q7. How to create Thread in Java and What are the ways?
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Threads in Java allow concurrent execution of multiple tasks. They can be created in multiple ways.
• Using the Thread class

• Implementing the Runnable interface

• Using the Executor framework

• Using the Callable interface with ExecutorService
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Q8. Write a SQL Query for having student table Name Subjects Marks Data like- abc Eng 19 abc Phy 17 abc Chem 20 xyz Eng 16 xyz Phy 18 xyz Chem 12 ..... output should be like a list display at the marks board ...read more
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Reverse a linked list.

Had given 2 java question which one is medium and other one was easy.

Q1. Circular linked list question
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Q2. SQL, dbms, oops connector basic question
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Q3. What is abstraction and encapsulation
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Abstraction is the concept of hiding complex implementation details and showing only the necessary information. Encapsulation is bundling data and methods that operate on the data into a single unit.
• Abstraction focuses on what an object does rather than how it does it

• Encapsulation restricts access to some of an object's components, protecting the object's integrity

• Abstraction allows for easier maintenance and modificat...read more
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Q4. Primary key, difference between primary key and super key
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Primary key uniquely identifies a record in a table, while super key is a set of attributes that can uniquely identify a record.
• Primary key is a subset of super key

• Primary key cannot have NULL values, while super key can

• Example: In a table 'Employee', 'EmployeeID' can be a primary key as it uniquely identifies each employee record, while 'EmployeeID, DepartmentID' can be a super key
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