Interview Q&A / Java
Java interview questions
Collections, the JVM, strings, exceptions and threads, the backbone of most campus placement rounds.
Prefer rapid revision? Practise Java short interview answers →
- What is a functional interface in Java and which built-in ones should you know?
A functional interface has exactly one abstract method, so a lambda can implement it. Core ones are Predicate (test), Function (apply), Consumer (accept) and Supplier (get). @FunctionalInterface makes the compiler check the rule.
BeginnerQuick answer1 min read