Data Structures and Algorithms (DSA) Interview Questions: Implement a data structure for a least recently used (LRU) cache. Explain the difference between depth-first search (DFS) and breadth-first search (BFS) algorithms. When would you use one over the other? Implement a function to check if a binary tree is balanced. Explain the concept of dynamic programming and provide an example problem where it can be applied. Java Interview Questions: Discuss the differences between the ArrayList and LinkedList classes in Java. When would you choose one over the other? Explain the concept of multithreading in Java and discuss synchronization techniques. Implement a custom exception class in Java and demonstrate its usage. Describe the principles of object-oriented programming (OOP) and provide examples of inheritance, polymorphism, and encapsulation. Discuss the advantages and disadvantages of using Java's HashMap class compared to Hashtable. React and JavaScript Interview Questions: Describe the React component lifecycle methods and when each one is invoked. Explain the concept of "virtual DOM" in React and how it enhances performance. Implement a higher-order component (HOC) in React and explain its purpose. Discuss the differences between JavaScript's var, let, and const keywords and when to use each. Explain the concept of closures in JavaScript and provide an example of how they can be used effectively.