Preparing for Java Interview?

My books Grokking the Java Interview and Grokking the Spring Boot Interview can help

Download a FREE Sample PDF

Friday, February 25, 2022

Review - Is Coursera's Cybersecurity Specialization by Maryland University worth It in 2024?

Cyber security is the science behind protecting the company's infrastructure, including employees' computers, their network, the servers where they host the web application, and the database of users' information or any sensitive information. They use some tools to assess the security of their infrastructure and to discover new vulnerabilities.

How to Prepare for Google Cloud Network Engineer Exam in 2024

Hello guys, if you are preparing for the Google Cloud Network Engineer exam or want to become a Google Certified Engineer in 2024 then you have come to the right place.  In the past, I have shared the best Google Cloud Platform courses as well many more resources to prepare for Google cloud Digital Leader, Google Cloud Developer, Google Cloud Data Engineer, and other exams and in this article, we are going to discuss a step by step guide to prepare for Google Cloud Network Engineer certification. This guide not only gives you information about the actual exam but also shares useful resources like books, online courses, and mock tests, both free and paid which you can take to prepare well for this exam. 

Thursday, February 17, 2022

How to fix @Autowired - No qualifying bean of type found for dependency in Spring Boot? [Solved]

Hello guys, if you are working in a Java and Spring Boot project and you are getting errors like "@Autowired - No qualifying bean of the type found for dependency " then you have come to the right place. Earlier, I have shared how to solve error creating bean with name in Spring framework and In this tutorial, we are going to discuss how to fix @Autowired - No qualifying bean of the type found for dependency. When we come across the org.springframework.beans.factory, we need to be careful. Whether there isn't a qualifying bean of type XXXX accessible, we should see if there is a spring bean called XXXX in the runtime. In most cases, we simply try to inject a bean that isn't defined.

Monday, February 14, 2022

Top 5 Courses to Crack Google Cloud Digital Leader Certification Exam in 2024 - Best of Lot

Hello friends, we are here again today for another exciting topic to discuss. But, today we are not gonna discuss something which is related to Java or any other language or spring boot. Today we are gonna discuss Google Cloud Platform Digital Leader Certification which is immensely practical and has the potential to land you very high-paying jobs. If you are preparing for Google Cloud Professional Digital Leader certification and looking for the best prep material and resources then you have come to the right place. Earlier, I have shared the best Google Cloud courses for beginners and today we are gonna take a look at the best available Google cloud courses online. 

Top 5 Practice Tests & Courses to Crack Azure IoT Certification AZ-220 Exam in 2024 - Best of Lot

Hello guys, if you are preparing for the AZ-220 exam or Azure IoT certification in 2024 and looking for the best AZ-220 certification courses then you have come to the right place. In the past, I have shared the best AZ-900 courses, best AZ-104 courses, and best AZ-204 courses and in this article, I am going to share the best online courses to crack Azure IoT certification or AZ-220 exam. These are the best resources to prepare for this exam and curated from popular sites like Udemy, Coursera, and Pluralsight.  Before we get to the best certification courses that you can use to clear the IoT AZ-220 certification exam, let me tell you what exactly is this AZ-220 Certification. 

Saturday, February 12, 2022

How to delete a key value pair from a HashMap during Iteration in Java - Example tutorial

Suppose you have a Map or Dictionaries like HashMap or Hashtable, which contains key-value pairs like books and their prices, and you want to delete all books whose prices are greater than 40 USD, how do you that in Java? This is one of the most common scenarios while developing Java applications and many Java programmers, will say that they will iterate over Map and check each entry and then use the remove(Object key) or remove(Object key, Object value) methods from java.util.Map to delete any mapping where the value is greater than 40 USD. Though the approach is right, the answer is wrong.

Friday, February 11, 2022

How to use Array in Java? Example Tutorial

The array is one of the most important data structures in any programming language, at the same time different programming languages implement and treat the array differently. Anyone who is done some programming knows the value of an array and the importance of knowing about array type, using them in their program. Together with a linked list, the array forms a set of basic data structures. Though Java offers excellent Collection API and some of the collection classes like ArrayList and  HashMap, they are internally based on the array.

Thursday, February 10, 2022

Top 30 Java Phone Interview Questions Answers for Freshers, 1 to 2 Years Experienced

Hello guys and ladies, in this article, I am sharing 30 core Java technical questions, from screening and phone rounds of interviews. In telephonic interviews, questions are short, fact-based and Interviewer expects a to-the-point reply and some keywords in answers. Accordingly, I have given very short answers to all these questions, only the main points; just to make this a revision post and not the main source for preparation. For thorough preparation, my master list of 140+ Java questions is a better one to start with. I am also expecting every Java programmer to know answers to all these Java technical questions if he has more than 4 to 5 years of experience. It's only freshers and junior developers who need to do a bit of research to understand topics well.

5 Benefits of using interface in Java and Object Oriented Programming

Interface in Java is a simple concept but many programmers fail to realize their actual use, including me. When I started learning Java programming, I learned interface is something where you can declare functions but cannot define them. To me, they were useless at that time because there was no code to do anything. It took me years to realize how useful an interface can be. They are not intended to do things but they are actually facilitators. They provide abstraction and give the flexibility to change your program in the future. That's why it's very important for a Java programmer to understand the benefits of interfaces and realize how and when to use them in code. 

Wednesday, February 9, 2022

Top 15 Data Structures and Algorithm Interview Questions Answers for Java Programmer

Data structures and algorithm questions are an important part of any programming job interview, be it a Java interview, a C++ interview, or any other programming language. Since data structures are core programming concepts, it's mandatory for all programmers, to know basic data structures like the stack, linked list, queue, array, tree, and graph. Though trees and graphs are on the tougher side, I still see programmers get familiar will all these. Any list of programming job interview questions is incomplete without questions from data structures and algorithms. Similarly, while going on questions from data structure you may get some programming exercise as well e.g. swapping numbers without temp variable.

Tuesday, February 8, 2022

Difference between SOAP and RESTful Web Service in Java

Though both SOAP and RESTful web services allow a client to query the server for some information, the way they are implemented and used is quite different. The main difference between SOAP and REST is that the former provides a standard of communication between client, server, and other parties and has restricted a set of rules and format, while REST leverages the ubiquity of HTTP protocol, in both client and servers, to allow them to communicate with each other regardless of their implementation. In short, getting data from a RESTful web service requires less headache than getting data from a SOAP web service.

3 Ways to Read File line by line in Java 8? Examples

Java 8 has added a new method called lines() in the Files class which can be used to read a file line by line in Java. The beauty of this method is that it reads all lines from a file as Stream of String, which is populated lazily as the stream is consumed. So, if you have a huge file and you only read the first 100 lines then the rest of the lines will not be loaded into memory, which results in better performance. This is slightly different from the Files.readAllLines() method (which reads all lines into a List) because this method reads the file lazily, only when a terminal operation is called on Stream like forEach(), count(), etc. By using the count() method you can actually count a number of lines in files or the number of empty lines by filtering empty lines.

Sunday, February 6, 2022

When to use intern() method of String in Java? Example

The String.intern() method can be used to deal with the String duplication problem in Java. By carefully using the intern() means you can save a lot of heap memory consumed by duplicate String objects. A String object is said to be duplicated if it contains the same content as another string but occupied a different memory location e.g. str1 != str2 but str1.equals(str2) is true. Since the String object consumes a large amount of heap memory in the average Java application, it makes sense to use the intern() method to reduce duplication and take advantage of the String pool feature provided by Java. You can use the intern() method to intern a String object and store them into the String pool for further reuse.

2 Examples to read Zip Files in Java, ZipFile vs ZipInputStream - Tutorial

ZIP format is one of the most popular compression mechanisms in the computer world. A Zip file may contain multiple files or folders in compressed format.  Java API provides extensive support to read Zip files, all classes related to zip file processing are located in the java.util.zip package. One of the most common tasks related to zip archive is to read a Zip file and display what entries it contains, and then extract them in a folder. In this tutorial, we will learn how to do this task in Java. There are two ways you can iterate over all items in a given zip archive, you can use either java.util.zip.ZipFile or java.util.zip.ZipInputStream. Since a Zip file contains several items, each of them has a header field containing the size of items in a number of bytes. This means you can iterate all entries without actually decompressing the zip file.

Saturday, February 5, 2022

How to split a comma separated String in Java? Regular Expression Example

You can use the String.split() function or StringTokenizer class to split a comma-separated String in Java. Since splitting a String is a very common functionality, Java designers have provided a couple of split() methods on java.lang.String class itself. These split() function takes a regular expression and split the String accordingly. In order to parse a comma-delimited String, you can just provide a "," as a delimiter and it will return an array of String containing individual values. The split() function internally uses Java's regular expression API (java.util.regex) to do its job.

Friday, February 4, 2022

How to access Private Field and Method Using Reflection in Java? Example Tutorial

Reflection in Java is a very powerful feature and allows you to access private methods and fields which is not possible by any other means in Java and because of this feature of reflection many code coverage tools, static analysis tools,s and Java IDE like Eclipse and Netbeans has been so helpful. In the last article, we have seen details about private keywords in Java and learned why we should always make fields and methods private in Java. There we have mentioned that private fields and methods are only accessible in the class they are declared but with reflection, you can call the private method and access private fields outside the class. In this article, we will see a simple example of accessing a private field using reflection and invoking a private method using reflection in Java.

Tuesday, February 1, 2022

Top 5 Courses to Learn Swagger or Open API for Beginners in 2024 - Best of Lot

 Hello guys, if you want to learn Swagger and looking for the best online courses then you have come to the right place. In the past, I have shared the best REST API courses as well best Postman courses, one of the best tools to test REST API and in this article, I am going to share the best online courses to learn Swagger in 2024. I have curated this list from my favorite online learning platform like Udemy, Pluralsight,  and Coursera and they are suitable for both beginners and intermediate developers who want to master the Swagger tool. But before we jump into these courses Let us start with the simple stuff first. What exactly is Swagger and Open API?

Top 5 Online Courses to Learn REST Assured for Testing in 2024 - Best of Lot

Hello guys, if you want to learn REST Assured tool for testing your API and RESTful Web services and looking for the best online courses to learn REST Assured then you have come to the right place. In the past, I have shared the best online courses to learn various REST API development tools like Postman, SoapUI, and Selenium, and today, I am going to share the best REST Assured courses to learn this useful tool in 2024. These are the best resource I can find to learn REST assured, particularly when it comes to choosing online courses and they are from popular online platforms like Udemy and Pluralsight. You can join one or two of these courses to master this excellent tool to automate your REST API Testing.