Java Developer Interview Questions
In your interview for a java developer position, be prepared to answer technical questions that test your understanding of Java basics. Interviewers may also ask open-ended questions to assess your coding and problem-solving abilities. Prepare for non-technical questions that focus on time management, interpersonal communication, and work ethic.
Top Java Developer Interview Questions & How to Answer
Here are three java developer interview questions and how to answer them:
Question #1: What is the difference between HashTable and HashMap in Java?
How to answer: Interviewers use technical questions to assess your formal training and understanding of the Java programming language. Use your answer to demonstrate your communication skills. Even if you have been coding for some time, it can be helpful to review Java basics before your interview.
Question #2: Write a program to determine if 243 is an Armstrong number.
How to answer: Interviewers use open-ended questions to test your coding skills. This question allows the employer to assess your ability to solve a problem using a Java algorithm. Explain your thinking process as you use a code editor or whiteboard to solve the problem.
Question #3: How do you produce quality code when you have several Java projects to complete at once?
How to answer: Java developers often juggle multiple projects at the same time. Interviewers use questions such as this to test your time management and organizational skills. Employers are also trying to assess your commitment to quality work. If you have experience as a developer, include examples from your work history that demonstrate high-quality work and effective time management.
Implement a method to determine whether a string is a palindrome.
4 Answers↳
Take a string as function parameter. Copy this str value into a new var, then use .reverse() thereupon. Compare the reversed copy back against original string using turnery operator to set resVariable to "true" : "false". Return resVariable. Less
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(Using .split(""), as well as .join(""))
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const palindrome = (str) => str == str.reversed() palindrome('hello') // false palindrome('eve') // true Less
Write a function to print the first letter of every word in a string.
4 Answers↳
public String getFirstLetters(String text) { String firstLetters = ""; text = text.replaceAll("[.,]", ""); // Replace dots, etc (optional) for(String s : text.split(" ")) { firstLetters += s.charAt(0); } return firstLetters; } Less
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let sentence = 'Big Green Dog' let words = sentence.split(' ') words.map((word) =>{ word.split('') console.log(word[0]) }) //output "B" "G" "D" Less
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public static void PrintFirstLetter( String s ){ If ( s.length == 0 ){ return; } String [ ] Words = s.split( “ “ ); for ( String word : Words ) { System.out.println( word.charAt(0)); } } Less
How would you scale access to a system like Twitter
3 Answers↳
I was thinking geographically distributed servers.
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Cf
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There's probably no real correct answer, though the solutions go from common to esoteric in a pretty normal progression: caching, shared-cache like memcache, optimize usage, prefetch, then get creative. This is more about testing reasoning and how far you'll go to solve a problem. Less
Write a method to determine if a string starts with an uppercase letter.
2 Answers↳
wouldn't it just be return string.charAt(0) == string.charAt(0).toLowerCase()
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bool lower(string s) { if (s.length() == 0) {return false;} char f = s.at(0); return (f > 64 && f < 91); // ascii values } Here’s a C++ implementation that might (not) work. Not so good with Java. Less
1.Java Basics. 2.Plethora of Multithreading questions.GC 3.Simple data structure. (BFS) variation 4.Database Basics
1 Answers↳
I fumbled in 1 questions which was the nail in the coffin.
Q: Why multiple inheritances are not supported in Java?
1 Answers↳
Because of diamond pattern, diamond pattern creates ambiguity and make problem for compiler. Anyway java supports multiple inheritances via interfaces. I think more convincing reason for not supporting multiple inheritance is complexity involved in constructor chaining, casting etc rather than diamond. Less
Lots of questions about arrays, lists and hashmaps
1 Answers↳
Focus more on how hashmap works and its applications
If you were responsible for development and launch of a billing system, how would you handle a critical situation?
1 Answers↳
My answer: 1. Pause or isolate the problematic process/workflow if possible 2. Study the logs and relevant data 3. Try to reproduce locally (in a sandbox) 4. Try to reproduce in staging environment 5. Add and deploy fix, enable the process/workflow back 6. Follow up with affected customers via support Less
attributes of <tr> tag
41 Answers↳
please let me know if anyone got Job
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36. If you get call then follow this interview experience
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How many of you waiting after 3rd round