Interview Q&A / Object-Oriented Programming

INTERVIEW Q&A · 69 QUESTIONS

Object-Oriented Programming interview questions

The four pillars, interfaces, abstract classes and design basics.

  1. How do you make a Singleton thread-safe in Java?

    Use eager initialisation, the holder class idiom, or an enum. If you need lazy creation with double-checked locking, the field must be volatile.

    IntermediateQuick answer1 min read