Java:
1. In detail about the Oops concepts
2. Differences between Abstract class and Interface?
3. Differences between the real time examples of both Abstract Class and Interface?
4. What is recursion and which data structure is used for recursion?
5. What is binary tree and binary search tree? 
Python:
1. What is tuple?
2. What is meant by dictionary?
3. Real time examples of both tuple and dictionary?
Javascript:
1. How do you extract an element in javascript?
2. Explain DOM Manipulations?
SQL:

1. What are views?
2. Advantages of views over tables?
3. What is join? Explain the types of joins?
4. What is normalization? Explain the types of normalizations?
5. What is unique key and foreign key constraints?
6. You are having a Collection of tables with a large complex data stored in it. How will you apply the normalization to it? Will it be difficult in splitting the tables for achieving normalization? What is your approach?