Barclay Java Interview Questions

Carvia Tech | April 23, 2019 | 2 min read | 163 views


OOP concepts

  • What is pass-by-value and pass-by-reference? Which mechanism is being used by Java?

Concurrency and multi-threading

  • What is an Immutable Class? Why is it important in multi-threading context? Can you write a Custom immutable class? What are semantics for writing an Immutable Class in java?

  • What is difference between sleep() and wait() method?

  • What is difference between Executor Framework and ForkJoinPool?

  • What is difference between Executor.submit() and Executor.execute() method?

  • What is ThreadLocal variable in Java?

  • How Garbage Collection works in Java, explain the underlying mechanism for any one of the Garbage Collector? Give few names of existing garbage collectors?

Collections framework

  • Write a code to iterate over a standard hashmap object in Java.

  • How will you use your custom Object as a Key inside hashing data-structure (Hashmap, ConcurrentHashmap, hashSet, etc.)?

  • What all things to keep in mind when you use Hashmap in multi-threaded environment?

  • Explain the working of put and get method of a hashmap class? How does equals() and hashcode() comes into picture there?

  • Write a code in java to remove elements of an array while iterating over it.

  • Discuss how HashSet works internally in java?

Algorithm problems

  • Write a recursive Java program to print Fibonacci Series?

  • How will find if the given input string is palindrome?

Design problems

  • What is Composite design pattern

  • Explain Decorator design pattern

  • Discuss through example, The Producer Consumer problem.

  • How will you design a distributed algorithm for Prime Number generation in Java? Discuss the Design only.

Misc problems

  • Explain database normalization and its various usages.

  • What are top 10 coding standards for code reviews in Java?


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