Java Developer

• What are the new features introduced in Java 8? (Learn)
• What is the difference between a lambda expression and a functional interface?

What is an Optional Class in Java? (Learn)

How do we achieve serialization, and where do primitive types take up memory?

How do you implement security, and how does OAuth work?

What are microservices, and how do you handle distributed transactions in microservices?

You are given an integer N. Your task is to return a 2-D ArrayList containing the pascal’s triangle till the row N.

A Pascal's triangle is a triangular array constructed by summing adjacent elements in preceding rows. Pascal's triangle contains the values of the binomial coefficient. For example in the figure below.

For example, given integer N= 4 then you have to print.

1  
1 1 
1 2 1 
1 3 3 1

Here for the third row, you will see that the second element is the summation of the above two-row elements i.e. 2=1+1, and similarly for row three 3 = 1+2 and 3 = 1+2.

What is GC and how does it work? (Learn)

What is multithreading, and how do you create threads? (Learn)

What is the difference between Comparator and Comparable? (Learn)

When should we use a List and when should we use a Map?

What is the difference between SQL vs NoSQL: When to use each? (Learn)