So, so easy. Java and Spring.

What is the purpose of garbage collection in Java, and when is it used?

The purpose of garbage collection is to identify and discard objects that are no longer needed by a program so that their resources can be reclaimed and reused. A Java object is subject to garbage collection when it becomes unreachable to the program in which it is used.

Describe synchronization with respect to multithreading.

With respect to multithreading, synchronization is the capability to control the access of multiple threads to shared resources. Without synchronization, it is possible for one thread to modify a shared variable while another thread is in the process of using or updating the same shared variable. This usually leads to significant errors.

Explain different ways of using threads.

Threads can be implemented by using the Runnable interface or by inheriting from the Thread class. The former is more advantageous because when you are going for multiple inheritance, the only interface can help.

collections