Java skills to master
Review classes, interfaces, inheritance, generics, exceptions, strings, arrays, and the collections framework.
Choose collections intentionally
Know when to use ArrayList, HashMap, HashSet, ArrayDeque, PriorityQueue, and tree-based collections.
- Understand generic types
- Compare equality correctly
- Use StringBuilder for repeated concatenation
- Know collection operation complexity
Communicate a complete solution
Use meaningful types and names, handle null and boundary cases, and explain the time and space complexity of your implementation.