Lowe's Home Improvement Interview Question

1. **What is scope?** 2. **What is singleton – why questions (Is thread)? Other ways also to implement singleton or what.** 3. **What is HashMap / ConcurrentHashMap? Copy-on-write, how everything exists for them and how to implement.** 4. **Difference between normal String, StringBuffer, StringBuilder – which to use when and why did you choose?** 5. **Implement custom comparator for sorting employee based on name alphabetical order. (Increase speed)**