Product Perfect

BlueJ is an integrated development environment (IDE) specifically designed for teaching Java and object-oriented programming. Developed in the late 1990s by Michael Kölling and John Rosenberg at Monash University, Australia, it was later maintained by the University of Kent, UK. The software simplifies the learning process with its visual interface and interactive capabilities. It has been adopted by many educational institutions worldwide to introduce students to Java programming. The software is open-source and freely available for use, making it a popular choice among educators and students alike.

Ask the right questions secure the right BlueJ talent among an increasingly shrinking pool of talent.

First 20 minutes

General BlueJ app knowledge and experience

The first 20 minutes of the interview should seek to understand the candidate's general background in BlueJ application development, including their experience with various programming languages, databases, and their approach to designing scalable and maintainable systems.

How would you create a new project in BlueJ?

To create a new project in BlueJ, you would go to 'Project' in the menu bar and select 'New Project'. You would then specify the project name and location.

What are the main components of the BlueJ interface?

The main components of the BlueJ interface are the 'Project' window, the 'Editor' window, the 'Object Bench', and the 'Terminal' window.

How would you compile a program in BlueJ?

You would right-click on the class that contains the main method and select 'Compile'. If there are no syntax errors, the class will be compiled successfully.

What is the purpose of the 'Object Bench' in BlueJ?

The 'Object Bench' is used to create and interact with objects. You can invoke methods on these objects and inspect their state.

How would you debug a program in BlueJ?

You would use the 'Debug' menu to set breakpoints, step into methods, step over methods, and continue execution. You can also inspect the state of objects and variables.

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What you’re looking for early on

Does the candidate have a solid understanding of BlueJ?

Can they demonstrate problem-solving abilities?

Do they have experience with Java?

How well does the candidate communicate?

Next 20 minutes

Specific BlueJ development questions

The next 20 minutes of the interview should focus on the candidate's expertise with specific backend frameworks, their understanding of RESTful APIs, and their experience in handling data storage and retrieval efficiently.

Describe the difference between 'step into', 'step over', and 'step out' in BlueJ's debugger.

'Step into' executes the next line of code and if it's a method call, it goes inside the method. 'Step over' executes the next line of code but doesn't go inside method calls. 'Step out' completes the execution of the current method and goes back to the caller method.

What are the benefits of using BlueJ for beginners in Java programming?

BlueJ simplifies the learning process by providing a clean and simple interface, visualizing the class structure, and allowing interaction with objects. It also has built-in tools for testing and debugging.

How would you create a new class in BlueJ?

You would right-click in the 'Project' window and select 'New Class'. You would then specify the class name and type.

What is the purpose of the 'Inspector' in BlueJ?

The 'Inspector' is used to inspect the state of an object. It displays the values of the object's fields.

How would you use the 'Code Pad' in BlueJ?

The 'Code Pad' is used to execute Java expressions and statements. You would type the code in the 'Code Pad' and press Enter to execute it.

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At this point, a skilled BlueJ engineer should demonstrate strong problem-solving abilities, proficiency in BlueJ programming language, and knowledge of software development methodologies. Red flags include lack of hands-on experience, inability to articulate complex concepts, or unfamiliarity with standard coding practices.

Digging deeper

Code questions

These will help you see the candidate's real-world development capabilities with BlueJ.

What does this simple BlueJ code do?
public class HelloWorld {
 public static void main(String[] args) {
 System.out.println("Hello, World!");
 }
}
This code prints 'Hello, World!' to the console.
What does this BlueJ code do?
public class Test {
 public static void main(String[] args) {
 int x = 5;
 int y = ++x;
 System.out.println(y);
 }
}
This code increments the value of 'x' before assigning it to 'y'. So, 'y' will be 6.
What will be the output of this BlueJ code?
public class ArrayTest {
 public static void main(String[] args) {
 int[] arr = {1, 2, 3, 4, 5};
 for(int i: arr) {
 System.out.print(i + " ");
 }
 }
}
This code will print the elements of the array 'arr' in a single line with a space between each element. So, the output will be '1 2 3 4 5 '.
What does this BlueJ code do?
public class ThreadTest extends Thread {
 public void run() {
 System.out.println("Thread is running.");
 }
 public static void main(String args[]) {
 ThreadTest t1=new ThreadTest();
 t1.start();
 }
}
This code creates a new thread and starts it. The new thread then prints 'Thread is running.' to the console.

Wrap-up questions

Final candidate for BlueJ Developer role questions

The final few questions should evaluate the candidate's teamwork, communication, and problem-solving skills. Additionally, assess their knowledge of microservices architecture, serverless computing, and how they handle BlueJ application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

Describe the difference between creating an object and creating a class in BlueJ.

Creating a class is defining a new type with its own methods and fields. Creating an object is instantiating a class, which means creating an instance of the class with its own state.

What are the steps to execute a method in BlueJ?

You would first create an object of the class that contains the method. You would then right-click on the object in the 'Object Bench' and select the method. If the method requires parameters, you would enter them in the dialog box.

How would you handle exceptions in BlueJ?

You would use try-catch blocks to handle exceptions. The code that might throw an exception is placed in the try block, and the code to handle the exception is placed in the catch block.

BlueJ application related

Product Perfect's BlueJ development capabilities

Beyond hiring for your BlueJ engineering team, you may be in the market for additional help. Product Perfect provides seasoned expertise in BlueJ projects, and can engage in multiple capacities.

BlueJ Consultive assessments

BlueJ Application Conversion Assessment BlueJ Application Integration Assessment BlueJ Data & Database Integration Assessment

Custom BlueJ development projects

Custom BlueJ App Conversion BlueJ Custom App Development Process App UI Design for BlueJ Facelifts

Hiring guide for BlueJ Engineers

BlueJ Developer Hiring Guide

What you’re looking for early on

The ideal back-end app developer

What you’re looking to see on the BlueJ engineer at this point.

BlueJ Consultive assessments

Custom BlueJ development projects