Java Online Test

About the test:

The Java test uses scenario-based and code-tracing questions to evaluate candidates' knowledge of core Java concepts such as OOPs, Classes, Exceptions, Collections and advanced topics such as concurrent programming with threads and handling relational databases. The test uses simple Java Coding questions to assess a candidate's ability to code in Java.

Covered skills:

Foundations of the Java syntax and semantics
Object-Oriented Programming
Java data structures (Strings; Arrays; Objects)
Exception handling
Functional programming with Lambdas & Streams API
SOLID principles

Basics of Web application programming
Working with Databases
Collections framework
Multi-threading
Core interface and implementations (List; Set; Map)

See all covered skills

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9 reasons why

Adaface Java Online Test is the most accurate way to shortlist Java Developers

Reason #1

Tests for on-the-job skills

The Java Online test helps recruiters and hiring managers identify qualified candidates from a pool of resumes and take objective hiring decisions. It reduces the administrative overhead of interviewing too many candidates and saves expensive engineering time by filtering out unqualified candidates.

The Adaface Java test screens candidates for the typical skills recruiters look for in a Java developer:

Experience with basic syntax and functions of Java
Experience with core Java concepts such as Strings, OOPs, Classes & Collections
Able to efficiently handle exceptions and errors
Working with relational databases & JDBC
Ability to detect and correct common programming errors at compile time and run time
Hands-on Java coding experience

Reason #2

No trick questions

Traditional assessment tools use trick questions and puzzles for the screening, which creates a lot of frustration among candidates about having to go through irrelevant screening assessments.

The main reason we started Adaface is that traditional pre-employment assessment platforms are not a fair way for companies to evaluate candidates. At Adaface, our mission is to help companies find great candidates by assessing on-the-job skills required for a role.

Why we started Adaface ->

Reason #3

Non-googleable questions

We have a very high focus on the quality of questions that test for on-the-job skills. Every question is non-googleable and we have a very high bar for the level of subject matter experts we onboard to create these questions. We have crawlers to check if any of the questions are leaked online. If/ when a question gets leaked, we get an alert. We change the question for you & let you know.

These are just a small sample from our library of 10,000+ questions. The actual questions on this Java Online Test will be non-googleable.

🧐 Question
Easy Custom Exception Exceptions	Solve
What does the following code output?
Hard Holding References	Solve
What does the following Java code output?
Medium Abstract Interface OOPs Interfaces	Solve
Given following interface: Which of these are correct classes?
Medium Garbage Collection Garbage Collection	Solve
After which line is "bs" object, created on Line 4, eligible for garbage collection?
Hard Static Init Blocks OOPs	Solve
What does the following code output? 1) G A B E D H 2) G B A D E H 3) G B A D E H C F 4) C F G A B E D H 5) C F G B A D E H 6) G C F A B E D H 7) G C F B A D E H
Easy Registration Queue Logic	Solve
We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount. For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition. ⚠️⚠️⚠️ Note: - The first line of the input is the length of the array. The second line contains all the elements of the array. - The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function. - You need to "print" the final result (not return it) to pass the test cases. For the example discussed above, the input will be: 5 20 70 -40 30 -10 Your code needs to print the following to the standard output: 20 70 30 -40 -10
Medium Longest Road logic hashmaps	Solve
A startup company E-Motors is building driverless automated cars. The car contains a sensor that checks the road quality for the next N meters to decide the optimal speed at which the cars should move. We are given recorded data by the sensor in the form of an array, where each element of the array is the rating given to 1 meter of the road in sequence. The rating given by the sensor is from 1 to 100, where 100 represents the road with the best condition, and any rating above 60 is optimal. Find the longest stretch of road in meters that is categorized as optimal by the sensor. The input is an array of "strings" which needs to be converted from string to integer/number inside the function.
Medium Visitors Count Strings	Solve
A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. Example: Input: WWMMWWCCC Expected Output: 4W3C2M Explanation: ‘W’ has the highest count, then ‘C’, then ‘M’. ⚠️⚠️⚠️ Note: - The input is already parsed and passed to a function. - You need to "print" the final result (not return it) to pass the test cases. - If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’. - If any of them have the same count, the output should follow this order - M, W, C.

	🧐 Question	🔧 Skill
	Easy Custom Exception Exceptions	2 mins Java	Solve
What does the following code output?
	Hard Holding References	2 mins Java	Solve
What does the following Java code output?
	Medium Abstract Interface OOPs Interfaces	2 mins Java	Solve
Given following interface: Which of these are correct classes?
	Medium Garbage Collection Garbage Collection	2 mins Java	Solve
After which line is "bs" object, created on Line 4, eligible for garbage collection?
	Hard Static Init Blocks OOPs	2 mins Java	Solve
What does the following code output? 1) G A B E D H 2) G B A D E H 3) G B A D E H C F 4) C F G A B E D H 5) C F G B A D E H 6) G C F A B E D H 7) G C F B A D E H
	Easy Registration Queue Logic	30 mins Coding	Solve
We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount. For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition. ⚠️⚠️⚠️ Note: - The first line of the input is the length of the array. The second line contains all the elements of the array. - The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function. - You need to "print" the final result (not return it) to pass the test cases. For the example discussed above, the input will be: 5 20 70 -40 30 -10 Your code needs to print the following to the standard output: 20 70 30 -40 -10
	Medium Longest Road logic hashmaps	25 mins Coding	Solve
A startup company E-Motors is building driverless automated cars. The car contains a sensor that checks the road quality for the next N meters to decide the optimal speed at which the cars should move. We are given recorded data by the sensor in the form of an array, where each element of the array is the rating given to 1 meter of the road in sequence. The rating given by the sensor is from 1 to 100, where 100 represents the road with the best condition, and any rating above 60 is optimal. Find the longest stretch of road in meters that is categorized as optimal by the sensor. The input is an array of "strings" which needs to be converted from string to integer/number inside the function.
	Medium Visitors Count Strings	30 mins Coding	Solve
A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. Example: Input: WWMMWWCCC Expected Output: 4W3C2M Explanation: ‘W’ has the highest count, then ‘C’, then ‘M’. ⚠️⚠️⚠️ Note: - The input is already parsed and passed to a function. - You need to "print" the final result (not return it) to pass the test cases. - If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’. - If any of them have the same count, the output should follow this order - M, W, C.

	🧐 Question	🔧 Skill	💪 Difficulty	⌛ Time
	Custom Exception Exceptions	Java	Easy	2 mins	Solve
What does the following code output?
	Holding References	Java	Hard	2 mins	Solve
What does the following Java code output?
	Abstract Interface OOPs Interfaces	Java	Medium	2 mins	Solve
Given following interface: Which of these are correct classes?
	Garbage Collection Garbage Collection	Java	Medium	2 mins	Solve
After which line is "bs" object, created on Line 4, eligible for garbage collection?
	Static Init Blocks OOPs	Java	Hard	2 mins	Solve
What does the following code output? 1) G A B E D H 2) G B A D E H 3) G B A D E H C F 4) C F G A B E D H 5) C F G B A D E H 6) G C F A B E D H 7) G C F B A D E H
	Registration Queue Logic	Coding	Easy	30 mins	Solve
We want to register students for the next semester. All students have a receipt which shows the amount pending for the previous semester. A positive amount (or zero) represents that the student has paid extra fees, and a negative amount represents that they have pending fees to be paid. The students are in a queue for the registration. We want to arrange the students in a way such that the students who have a positive amount on the receipt get registered first as compared to the students who have a negative amount. We are given a queue in the form of an array containing the pending amount. For example, if the initial queue is [20, 70, -40, 30, -10], then the final queue will be [20, 70, 30, -40, -10]. Note that the sequence of students should not be changed while arranging them unless required to meet the condition. ⚠️⚠️⚠️ Note: - The first line of the input is the length of the array. The second line contains all the elements of the array. - The input is already parsed into an array of "strings" and passed to a function. You will need to convert string to integer/number type inside the function. - You need to "print" the final result (not return it) to pass the test cases. For the example discussed above, the input will be: 5 20 70 -40 30 -10 Your code needs to print the following to the standard output: 20 70 30 -40 -10
	Longest Road logic hashmaps	Coding	Medium	25 mins	Solve
A startup company E-Motors is building driverless automated cars. The car contains a sensor that checks the road quality for the next N meters to decide the optimal speed at which the cars should move. We are given recorded data by the sensor in the form of an array, where each element of the array is the rating given to 1 meter of the road in sequence. The rating given by the sensor is from 1 to 100, where 100 represents the road with the best condition, and any rating above 60 is optimal. Find the longest stretch of road in meters that is categorized as optimal by the sensor. The input is an array of "strings" which needs to be converted from string to integer/number inside the function.
	Visitors Count Strings	Coding	Medium	30 mins	Solve
A manager hires a staff member to keep a record of the number of men, women, and children visiting the museum daily. The staff will note W if any women visit, M for men, and C for children. You need to write code that takes the string that represents the visits and prints the count of men, woman and children. The sequencing should be in decreasing order. Example: Input: WWMMWWCCC Expected Output: 4W3C2M Explanation: ‘W’ has the highest count, then ‘C’, then ‘M’. ⚠️⚠️⚠️ Note: - The input is already parsed and passed to a function. - You need to "print" the final result (not return it) to pass the test cases. - If the input is- “MMW”, then the expected output is "2M1W" since there is no ‘C’. - If any of them have the same count, the output should follow this order - M, W, C.

Reason #4

1200+ customers in 75 countries

With Adaface, we were able to optimise our initial screening process by upwards of 75%, freeing up precious time for both hiring managers and our talent acquisition team alike!

Brandon Lee, Head of People, Love, Bonito

Reason #5

Designed for elimination, not selection

The most important thing while implementing the pre-employment Java Online Test in your hiring process is that it is an elimination tool, not a selection tool. In other words: you want to use the test to eliminate the candidates who do poorly on the test, not to select the candidates who come out at the top. While they are super valuable, pre-employment tests do not paint the entire picture of a candidate’s abilities, knowledge, and motivations. Multiple easy questions are more predictive of a candidate's ability than fewer hard questions. Harder questions are often "trick" based questions, which do not provide any meaningful signal about the candidate's skillset.

Reason #6

1 click candidate invites

Email invites: You can send candidates an email invite to the Java Online Test from your dashboard by entering their email address.

Public link: You can create a public link for each test that you can share with candidates.

API or integrations: You can invite candidates directly from your ATS by using our pre-built integrations with popular ATS systems or building a custom integration with your in-house ATS.

Reason #7

Detailed scorecards & comparative results

Reason #8

High completion rate

Adaface tests are conversational, low-stress, and take just 25-40 mins to complete.

This is why Adaface has the highest test-completion rate (86%), which is more than 2x better than traditional assessments.

Reason #9

Advanced Proctoring

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How is the test customized for Senior Java developers?

For intermediate/ experienced candidates, we customize the assessment questions to include advanced topics and increase the difficulty level of the questions. This includes adding questions on topics like

Using abstract classes, encapsulation, polymorphism, and interfaces efficiently
Comparing the efficiency of two programs in terms of the resources used
Best practices of using collections in Java
Reflection API
Functional programming using Lambdas and Streams API
In-depth knowledge of exception handling and garbage collection in Java
Efficient concurrent programming techniques
Event-driven programming & Web application programming

The coding question for experienced candidates will be of a higher difficulty level to evaluate more hands-on usage of Java collections.

What roles can I use the Java Online Test for?

Java Developer
Java Programmer
Backend Developer
Senior Java Eningeer

What topics are covered in the Java Online Test?

Arrays

Objects

Strings

Data Structures

Reflection API

Functional programming

Lambdas

Streams API

Regular Expressions

JDBC

Working with Databases

Serialization & De-serialization

Object-oriented programming (OOP)

Classes & Objects

Web application programming

Annotations

Optionals

Modules

Java 8 Date/Time API

List, Set, Map interfaces

SOLID

Java Collections Framework

Searching

Sorting

Variables

Data Types

JSP

Servlets

Generics

Multi-threading

Exception Handling

File system Handling

Inheritance

Polymorphism

Debugging

Matrices

Event-Driven Programming

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The hiring managers felt that through the technical questions that they asked during the panel interviews, they were able to tell which candidates had better scores, and differentiated with those who did not score as well. They are highly satisfied with the quality of candidates shortlisted with the Adaface screening.

85%

reduction in screening time

View Full Case Study

Java Online Test FAQs

What type of questions will the Java Online Test include?

The test will have MCQ questions and coding questions. The coding question is designed to evaluate hands-on Java programming experience. The MCQ questions are scenario-based to evaluate on-the-job skills as opposed to just theoretical concepts.

How can I test multiple Java related skills in a single pre-employment test?

Our customized assessments allow you to test multiple skills in a single test. For example, suppose you are looking for a Java developer with knowledge of Spring and SQL. In that case, we customize an assessment to assess all the three skills in the test.

What skills are required for a Java role?

Depending on the role and industry, a Java developer might require these skills:

Understanding of Object-Oriented Programming concepts
Understanding of when to use design patterns such as Singleton, Factory, Fly-weight, Builder, Object Pool, Iterator, Strategy, Visitor, Composite. This skill is particularly important for senior Java developers who will have to work on the architecture of applications to design long-term solutions
Understanding of the class loading process and how class loaders work
Deep understanding of the nuanced world of performance, whether that be memory overhead, computation complexity, or speed
Knowledge of when memory is being allocated, from what context, and how it affects heap fragmentation
Familiarity with the various garbage collection algorithms, and how to use the profilers
Experience with JSP / Servlets, Web Frameworks like Struts / Spring, and Service-Oriented Architecture / Web Services – SOAP / REST
Ability to apply the most modern patterns and language features to existing systems
Experience in using technologies in the Java ecosystem: Struts, Spring, Maven, Gradle, Ant, JUnit, Spock, and Hibernate, among many others
Knowledge of the intricacies of SQL queries
Ability to learn new technologies and willingness to step out of comfort zone to explore and learn new skills

Can I combine multiple skills into one custom assessment?

Yes, absolutely. Custom assessments are set up based on your job description, and will include questions on all must-have skills you specify.

Do you have any anti-cheating or proctoring features in place?

We have the following anti-cheating features in place:

Non-googleable questions
IP proctoring
Web proctoring
Webcam proctoring
Plagiarism detection
Secure browser

Read more about the proctoring features.

How do I interpret test scores?

The primary thing to keep in mind is that an assessment is an elimination tool, not a selection tool. A skills assessment is optimized to help you eliminate candidates who are not technically qualified for the role, it is not optimized to help you find the best candidate for the role. So the ideal way to use an assessment is to decide a threshold score (typically 55%, we help you benchmark) and invite all candidates who score above the threshold for the next rounds of interview.

What experience level can I use this test for?

Each Adaface assessment is customized to your job description/ ideal candidate persona (our subject matter experts will pick the right questions for your assessment from our library of 10000+ questions). This assessment can be customized for any experience level.

Does every candidate get the same questions?

Yes, it makes it much easier for you to compare candidates. Options for MCQ questions and the order of questions are randomized. We have anti-cheating/ proctoring features in place. In our enterprise plan, we also have the option to create multiple versions of the same assessment with questions of similar difficulty levels.