First, HR called, but it was just a chat. Then the hiring manager called for five minutes and asked Java and HTTP-related questions. If he thought it was fine, then he would send three Java coding questions. The problem was the questions weren't very clear. For example, it specified only to define one class, BinaryTreeNode, but to use this to represent a tree. The tree itself should be a class. I finished with some getters and setters as standard, and I traversed the tree as well, as requested. However, the hiring manager felt I wrote too much code.

The second question was about only allowing two threads to run a method. So, I used a static volatile to define a variable, but the hiring manager couldn't understand volatile and considered my answer totally wrong.

What is the difference between ArrayList and Vector?

What is the difference between GET and POST?

What is SSL?