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Thursday, September 30, 2021

3 ways to convert String to JSON object in Java? Examples

It's very common nowadays to receive JSON String from a Java web service instead of XML, but unfortunately, JDK doesn't yet support conversion between JSON String to JSON object. Keeping JSON as String always is not a good option because you cannot operate on it easily, you need to convert it into a JSON object before you do anything else e.g. retrieve any field or set different values. Fortunately, there are many open-source libraries which allows you to create JSON object from JSON formatted String like Gson from Google, Jackson, and json-simple. In this tutorial, you will learn how to use these 3 main libraries to do this conversion with step-by-step examples.

Wednesday, September 29, 2021

QuickSort Algorithm Example in Java using Recursion - Tutorial

The Quicksort algorithm is one of the very popular sorting algorithms in programming, often used to sort a large array of numbers. Though there is numerous algorithm available to sort a list of objects, including integer, string, and floating-point number, quicksort is best for general purpose. It's a divide and conquers algorithm, where we divide the given array with respect to a particular element, known as 'pivot' such that the lower partition of the array is less than the pivot and upper partition elements of the array are higher than the pivot.

Top 18 CSS Interview Questions and Answers for Beginners and 1 to 2 years experienced

CSS is one of the three core technologies of the World Wide Web(WWW). A website is incomplete without CSS. The first feature of a website noted by the visitors is its presentation. It does not matter how excellent the behind-the-scenes of a website are, if the client-side view is not appealing, the website is almost a failure. Thus, CSS is as important as JavaScript.

How to remove a number from an Integer Array in Java? [Example Tutorial]

Hello guys, In the last article, you have learned how to reverse an array in place in Java, and today I have come back with another array-based coding interview question. It's also one of the frequently asked coding questions, not as popular as the previous one but still has been asked a lot of times on various Programming Job interviews, particularly to beginners. In this problem, you are asked to write a program to remove a given number from the given array. It may seem easy, but the trick is that because an array is a fixed data structure and you cannot change the length of the array once created. 

Tuesday, September 28, 2021

How to create an ArrayList from Array in Java? Arrays.asList() Example Tutorial

One of the common problems faced by junior and less experienced Java developers is converting an array to ArrayList e.g. they are getting an array from somewhere in their code and then want to create an ArrayList out of that so that they can add more elements and use other library methods which operate with ArrayList or List. The simplest way to convert an array to ArrayList is by using the Arrays.asList() method, which acts as a bridge between Collection classes and array data structure. This method returns a List that contains elements from an array. 

Difference between Method and Constructor in Java and OOP? Example

What is the difference between method and constructor in Java is a very common question in beginner-level Java interviews with 2 to 3-year experience. Since the constructor is kind of special and it has its own properties that separate it from any normal Java method, this question makes sense. The main difference between a Constructor and a Method is that you need to call the method explicitly but the constructor is called implicitly by the Java programming language during object instantiation. This is one of the special properties of constructors in Java and that's why all the object initialization code is put inside the constructor. 

Monday, September 27, 2021

How does Spring MVC Process HTTP Request [Flow]? DispatcherServlet Example Tutorial

One of the common interview questions in Spring MVC is, how does the DispatcherServlet process a request in Spring MVC? or What is the role of DispatcherServlet in the Spring MVC framework? This is an excellent question for any Java or Spring web developer because it exposed the candidate's knowledge about Spring MVC architecture and how its main components like Model, View, and Controller.   The answers to this question show how much you know about the Spring MVC framework and its working. 

Sunday, September 26, 2021

Top 17 Linux, SQL, and Multicasting Interview Questions Answers for 1 to 5 Years Experienced

Hello guys, If you have worked as a software developer or Java programmer then you know that SQL, Linux, and Networking fundamentals are essential skills for any Java developer, especially for server-side Java programmers. It actually doesn't matter whether you are applying for the job as a Java developer or C++ developer, Python developer or Ruby programmer, SQL and UNIX always have some role to play in your career. It's even essential for people who have less to do with programming like application support guys, business analysts, project managers, and subject matter experts.  Hence, it's imperative for any programmer or IT professional to prepare both SQL and UNIX well before going for any job interview.

Saturday, September 25, 2021

What is Diamond operator in Java? How and When to use? - Example Tutorial

The Diamond operator is a relatively new operator in Java which was first introduced in JDK 7  to improve type inference and reduce boilerplate Java coding. It is denoted with a closed angle bracket that resembles the shape of a diamond (<>) and that's why it's called the Diamond operator. If used correctly it can reduce typing and boilerplate coding in Java and result in much cleaner and readable code especially when you use Generics.  

Friday, September 24, 2021

3 ways to sort a List in Java 8 and 11 - Example Tutorial

There are multiple ways to sort a list in Java 8, for example, you can get a stream from the List and then use the sorted() method of Stream class to sort a list like ArrayList, LinkedList, or Vector and then convert back it to List. Alternatively, you can use the Collections.sort() method to sort the list. There is also a sort() method added to the List class itself. The Collections.sort() method is an older one and it's available from JDK 1.0 itself but List.sort() is a new method added in Java 8. This method accepts a Comparator if you want to sort a List in a custom order, otherwise, you can pass null if you want to sort a List on the natural order of their elements. 

Thursday, September 23, 2021

5 Free SQL Books For Beginners and Experienced - Download PDF or Read Online

There is no doubt that SQL is one of the most essential skills for Programmers, IT professionals, Software Engineers, Quality Analysts, Project Manager, Data scientists, Database admins, and Business Analysts. I had even mentioned this as one of the top skills in my post about 10 things every programmer should know, if you haven't read that yet, you can read it here, it's completely worth your time. Since many Enterprise applications use the relational database at their backend, like Oracle, Microsoft SQL Server, MySQL, it's crucial to learn SQL to work with those applications and use the data stored on those databases.

How Binary Search Algorithm Works? Java Example without Recursion

The binary search algorithm is one of the fundamental Computer Science Algorithms and is used to search an element in a sorted input set. It's much faster than the linear search which scans each and every element and improves performance from O(n) to O(logN) for searching an element in the array. In order to perform the binary search, you need a sorted array, so you can either ask the user to enter the array in sorted order or you should sort the array before performing the binary search. It's also one of the popular algorithms for Programming Job interviews. The interviewer often asks candidates to implement binary search algorithms by hand in their favorite programming languages like Java, C++, Python. or JavaScript.

How to sort a List or Stream by Multiple Fields in Java? Comparator comparing() + thenComparing Example

One of the common requirements in Java is to compare objects by multiple fields. For example, if you have a list of CreditCard objects and you want to compare them by their provider and credit limit I mean, first compare them by their providers like VISA, Master, or American Express and if they are from the same provider then compare them by their credit limit, also known as breaking ties. Before Java 8 this wasn't easy because you have to write nested codes to compare multiple fields of an object as there was no easy way to chain multiple Comparators in Java, but things have changed a lot from Java 8.

Wednesday, September 22, 2021

How to solve java.lang.NoClassDefFoundError: org/springframework/beans/factory/SmartInitializingSingleton in Spring Boot [Solved]

Problem:
I was trying to run a HelloWorld program using Spring Boot when I got this error:

Exception in thread "main" java.lang.IllegalStateException: Could not evaluate condition on org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration#propertySourcesPlaceholderConfigurer due to internal class not found. This can happen if you are @ComponentScanning a springframework package (e.g. if you put a @ComponentScan in the default package by mistake)
at org.springframework.boot.autoconfigure.condition.SpringBootCondition.matches(SpringBootCondition.java:52)
at org.springframework.context.annotation.ConditionEvaluator.shouldSkip(ConditionEvaluator.java:92)
at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForBeanMethod(ConfigurationClassBeanDefinitionReader.java:174)
at org.springframework.context.annotation.ConfigurationClassBeanDefinitionReader.loadBeanDefinitionsForConfigurationClass(ConfigurationClassBeanDefinitionReader.java:136)

Tuesday, September 21, 2021

10 Examples to DateTimeFormatter in Java 8 to Parse, Format LocalDate and LocalTime

Parsing and formatting dates are other essential topics while working with date and time in Java. Even though the old Date API had the SimpleDateFormat and DateFormat class to support the formatting of date and parsing texts, they were not simple, or should I say there were just simple in writing the wrong code. You might know that SimpleDateFormat was not thread-safe and quite heavy to be used as a local variable. Thankfully, this has been sorted now with a new LocalDateTime class and DateTimeFormatter class, which has several inbuilt formats.

How to declare and Initialize two dimensional Array in Java with Example

An array of more than one dimension is known as a multi-dimensional array. Two of the most common examples of multi-dimensional arrays are two and three-dimensional arrays, known as 2D and 3D arrays, anything above is rare. I have never seen 4-dimensional arrays, even 3D arrays are not that common. Now the question comes when to use a multi-dimensional array? Any real-life example? Well, 2D arrays are very common on platform games like Super Mario Bros to represent screen or terrain; 2D arrays can also be used to represent structures like a spreadsheet, or to draw board games like Chess, which requires an 8x8 board, Checkers and  Tic-Tac-Toe, which requires 3 rows and 3 columns.

Top 10 Books Every Programmer Should Read

There is a saying that if you learn from your mistakes, you will only going to learn few things, but if you learn from other's mistakes, you can learn a lot of things in a short time, and what could be a better way to learn from someone's experience then reading books. Programming as a career is about constant learning and updating yourself, but unfortunately, there is no right way to begin. Schools and Colleges are far behind when it comes to real-world programming, and every Computer Science graduate is not lucky to work in a company that is great in training. The other viable option is to read books, join online courses, and follow advice from the great programmer and authors who are gone on that path, and learning from the book is the most tried and trusted way of all of them.

How to use Spread operator and Rest parameter in JavaScript? Example Tutorial

Hello guys, if you are wondering what is Spread and Rest operator is in JavaScript are and how to use them in code then you have come to the right place. Earlier, I have shared some fundamental JavaScript concept tutorials like == vs === operator, hoisting, and destructuring, and in this JavaScirpt article, I am going to talk about Spread and Rest operators. JavaScript came out twenty-five years ago. Since then, it has changed a lot. First, it became the top programming language for client-side web development, and then with the emergence of Node.js, it also became the top player in server-side development. 

Monday, September 20, 2021

10 Examples of Collectors + Stream in Java 8 | Grouping By, Partition By, Joining, and Counting

As the name suggests, the Collectors class is used to collect elements of a Stream into Collection. It acts as a bridge between Stream and Collection, and you can use it to convert a Stream into different types of collections like List, Set, Map. Btw, it is not just limited to that, it even provides functionalities to join String, group by, partition by, and several other reduction operators to return a meaningful result. It's often used along with the collect() method of Stream class which accepts Collectors. In this article, you will learn how to effectively use java.util.stream.Collectors in Java by following some hands-on examples.

What is Variable and Function Hoisting in JavaScript? Example Tutorial

Hoisting is a complex concept in JavaScript. Like other major programming languages, variables and functions are an important part of JavaScript. Being a dynamically typed programming language, the variable declaration does not require specifying variable types. JavaScript also supports functions. But there is a catch. When variables and functions are declared in JavaScript, a process called hoisting takes place, and if you don't know this important concept you may struggle reading and understanding code but don't worry. In this article, I will teach you what is hoisting in JavaScript and give you real-world examples of the function and variable hoisting to start with.  

Sunday, September 19, 2021

Top 5 Object Oriented Analysis and Design Interview Questions for Programmers, Software Engineers

Testing the design skill of a candidate is quite common in programming job interviews. Questions like, how do you design a vending machine or a traffic control system are very popular in object-oriented programming language interviews, like Java and C++. Designing a software System requires good experience and knowledge of tools of object-oriented design and analysis. You should not only be good at OOP fundamentals like Abstraction, Inheritance, Polymorphism, Encapsulation, Coupling, Cohesion, Association, Aggregation, or Composition but also on several crucial object-oriented design principles like SOLID Principles of Object-Oriented Design, which is the building block for writing flexible and maintainable code.

What is Destructuring in JavaScript? Example Tutorial

Arrays and objects play a very important role in programming. Every major programming language supports arrays and objects. Both arrays and objects are used to store data. The concept is simple but very powerful. JavaScript also supports arrays and objects. In fact, they are a very important part of modern JavaScript development. It does not matter if you are working on the frontend or backend, you are going to use arrays and objects. Over time, more and more features were added in JavaScript to make it easy to work with arrays and objects. 

Saturday, September 18, 2021

Difference between first level and second level cache in Hibernate

The main difference between the first level and second level cache in Hibernate is that the first level is maintained at the Session level and accessible only to the Session, while the second level cache is maintained at the SessionFactory level and available to all Sessions. This means, you can use the first-level cache to store local data, i.e. the data which is needed by the Session, and you can use the second-level cache to store global data, i.e. something which can be shared across sessions. This is also one of the frequently asked Hibernate Interview questions and accessible in both telephonic rounds as well as on the face-to-face interviews, in both fresher and experienced level interviews.

Difference between IN, OUT, and INOUT parameters in JDBC Stored Procedure? Answer

Hello guys, Java Database Connectivity, the JDBC API supports three types of parameters, I mean, IN, OUT, and INOUT. They are used to bind values into SQL statements. An IN parameter is the one whose value is unknown when the SQL statement is created and you bind values using various setXXX() method depending upon the type of column those IN parameter refers in SQL query. For example in SQL query, SELECT * from EMPLOYEE where EMP_ID=? if the EMP_ID is a VARCHAR column then you must call the setString() method to pass the value to the IN parameter. 

Friday, September 17, 2021

3 Ways to convert Date to LocalDate in Java 8 - Example, Tutorial

One of the great features of Java 8 is the new Date and Time API which is intended to fix existing issues related to mutability and thread-safety with existing java.util.Date class. But given java.util.Date is used very heavily across all the Java applications, you will often end up with a situation where you need to convert java.uti.Date to java.time.LocalDate while working in Java 8. Unfortunately there is no toLocalDate() method in the java.util.Date class. Though, you can easily convert Date to LocalDate if you are familiar with how new and old API classes map to each other.

Thursday, September 16, 2021

How to create a custom tag in JSP? Steps and Example

You can create a custom tag in JSP either by implementing the SimpleTag interface or extending SimpleTagSupport class. Custom tags are introduced in JSP 2.0 in an effort to minimize Java code from JSP to keep them maintainable and allow page authors to work more in HTML or XML, like environment than writing Java codes. SimpleTag and SimpleTagSupport allow you to create a custom tag in JSP. It's easier to start with SimpleTagSupport class because it implements all methods of the SimpleTagSupport interface and if you are writing a basic tag then you just need to override the doTag() method of this class. 

Wednesday, September 15, 2021

Static Class, Static Variable, Keyword, and Static Method Examples in Java - Tutorial

What is static in Java
Static in Java is related to class if a field is static means it belongs to the class, similarly static method belongs to classes and you can access both static method and field using the class name, for example,  if count field is static in Counter class than you can access it as Counter.count, of course, subject to restriction applied by access modifier like private fields are only accessible in class on which they are declared, protected fields are accessible to all classes in the same package but only accessible in subclass outside the package, you can further see private vs protected vs public for complete details on access modifier. 

How to use lifecycle methods in functional components in React.js? useEffect() hook Example Tutorial

Hello guys, if you have been following my blogs then you know that I have launched a new series - React for Java developers and this is the 4th article on the series. Earlier, we have seen state management in React, Redux, and useState hooks example, and in this article, you will learn about how to use lifecycle methods in functional React components. Lifecycle methods are powerful features provided by React.js in the class-based components. Each of the lifecycle methods executes at a particular time during the lifecycle of a component. 

Tuesday, September 14, 2021

How to compare two Arrays in Java to check if they are equal - [String & Integer Array Example]

Hello guys, one of the common Programming, the day-to-date task is to compare two arrays in Java and see if they are equal to each other or not. Of course, you can't compare a String array to an int array, which means two arrays are said to be equal if they are of the same type, has the same length, contains the same elements, and in the same order. Now, you can write your own method for checking array equality or take advantage of Java's rich Collection API. Similar to what you have seen while printing array values in Java, java.util.Arrays class provides convenient methods for comparing array values.

What is the use of DispatcherServlet in Spring MVC? Interview Question Example

Hello guys, In today's article we are going to discuss one interesting and the important Spring MVC concept, which is also a popular Spring Interview question. How DispatcherServlet works internally in Spring MVC or What is the role of DispatcherServlet in Spring MVC are some of the frequently asked Spring MVC Interview Questions. You might have seen them already during your previous Java web development interviews but if you have not, it's a good question to know. In this article, I'll answer these questions by explaining What is DispatcherServlet and its importance in Spring MVC. The DispatcherServlet is one of the important components of the Spring MVC web framework and acts as a Front Controller.

Monday, September 13, 2021

What is Redux Thunk in React.js? Example tutorial

Hello folks, This is the 3 part of my React for Java developer series and in the past two articles we have been focusing on statement management in React and we have seen that how to use manage state using Redux and useState hooks. And, in this article, we will learn about Redux Thunk, another useful concept when it comes to statement in React.js. State management is one of the most important concepts in react. If you are a react developer, then you must have used state in your project. There is no react project without a state. The state is defined as an instance of a component. It is an object that controls the behavior of a component. 

How to Convert or Print Array to String in Java? Example Tutorial

Array and String are very closely related, not just because String is a character array in most of the programming language but also with popularity - they are two of the most important data structure for programmers. Many times we need to convert an array to String or create an array from String, but unfortunately, there is no direct way of doing this in Java. Though you can convert an array to String by simply calling their toString() method, you will not get any meaningful value.  If you convert an Integer array to a String, you will get something like I@4fee225 due to the default implementation of the toString() method from the java.lang.Object class. Here, I show the type of the array and content after @ is hash code value in hexadecimal.

How to Format Date to String in Java 8 [Example Tutorial]

One of the common programming tasks in Java is to change the date format of a given Date or String. For example, you have something like "2017-01-18 20:10:00" and you want to convert it that date into "2017-01-18", or you want to convert from dd-MM-YY to MM-dd-YY or to any other format of your choice and need, but a valid date format as per Java specification. How will you do that? Well, it's not that difficult. It's just a two-step process. In the first step, you need to parse String to create an equivalent date using the current format, and then once you got the date, you need to again convert it back to String using the new format. The same process is repeated in both Java 8 and before, only corresponding API and class changes.

Top 15 Linux and UNIX Interview Questions and Answers for 1to 3 Years Experienced

UNIX and Linux Interview Questions and Answers
Hello guys, if you are preparing for technical interviews like Software developer or IT support and looking for some frequently asked Linux and UNIX interview questions then you have come to the right place. In the past, I have shared free Linux courses and today, I am going to share popular Linux and UNIX questions from technical interviews. You might already know that questions from various UNIX operating systems like Solaris, Linux, IBM AIX, or any other UNIX operating system are asked on different support and programming interviews and a good knowledge of essential UNIX concepts and commands goes a long way in cracking these interview as well as working efficiently in your day job. 

Saturday, September 11, 2021

What is Redux and how to use it? Example Tutorial

Managing state efficiently is very important in a react application. A React application depends on its state. React provides in-built support to manage the state but as the application grows, this in-built support becomes inefficient. So to manage the state of a large and complex react application, we have to use third-party state management libraries. Redux is by far the most popular state management library. It is heavily used with react and if you are planning to work in a real-time react project, you will encounter redux.

Friday, September 10, 2021

How to Convert a List to Map in Java 8 - Example Tutorial

One of the common tasks in Java programming is to convert a list to a map and I have written about this in the past and today we'll see how Java 8 makes this task easier. Btw, be it Java 7 or Java 8, you need to keep something in mind while converting a list to a map because they are two different data structures and have completely different properties. For example, the List interface in Java allows duplicate elements but keys in a Map must be unique, the value can be duplicated but a duplicate key may cause a problem in Java 8. This means a List with duplicates cannot be directly converted into Map without handling the duplicate values properly. 

Can you Overload or Override main method in Java? Example

One of the common doubts among Java beginners while learning the overloading and overriding concept is, whether it's possible to overload the main in Java? Can you override the main method in Java? How will JVM find if you change the signature of the main method as part of the method overloading? etc. These are good questions and show the curiosity and application of knowledge of students, so if you are the tutor you must answer these questions. If you don't know the answer to this question, don't worry, just read this article till the end and you will find the answer yourself.  I have tried to explain in simple words but if you still can't get it, feel free to comment and I will try to help you personally. 

Thursday, September 9, 2021

How to use Map.compute(), computeIfPresent() and ComputerIfAbsent in Java? ConcurrentHashMap Example

The JDK 8 has added several useful methods in existing interfaces e.g. java.util.Map, java.util.Collection, and java.util.concurrent.ConcurrentMap. Thanks to default methods, the much-needed evolution of existing interfaces becomes possible. Out of many useful methods, one method which stands out to me is the compute() method, which allows you to update a value in ConcurrentHashMap atomically. As per Java documentation, The compute() function tries to compute a mapping for the specified key and its current mapped value (or null if there is no current mapping). The entire function is performed atomically.

What is Method Overloading, Overriding, Hiding, Shadowing and Obscuring in Java and Object-Oriented Programming?

Hello guys, today, I am going to explain a couple of fundamental object-oriented programming concepts in Java, like Overloading, Overriding, Hiding, Shadowing, and Obscuring. The first two are used in the context of a method in Java while the last three are used in the context of variables in Java. Two methods with the same name and same class but the different signature is known as overloading and the method is known as an overloaded method while a method with the same name and same signature but in parent and child class is known as overriding. On the other hand,  Hiding is related to overriding since the static and private method cannot be overridden, if you declare such methods with the same name and signature in parent and child class then the method in the child class will hide the method in the parent class.

Wednesday, September 8, 2021

When to use PUT or POST in a RESTful Web Service? Answer

Hello guys, if you are confused about whether to use PUT or POST for updating a resource using RESTful web service then you have come to the right place. In the past, I have shared the best RESTful web service books and courses and today, I am going to share some tips to choose between PUT and POST while designing your RESTful web services. Btw, you are not alone, one of the most common confusion among web developers is the choice of PUT or POST HTTP method for creating and updating a resource while developing RESTful Web Services. Since both can be used to submit data, you can use either POST or PUT to create or update a resource.
 

How to sort HashMap by values in Java 8 [using Lambdas and Stream] - Example Tutorial

In the past, I have shown you how to sort a HashMap by values in Java, but that was using traditional techniques of the pre-Java 8 world. Now the time has changed and Java has evolved into a programming language that can also do functional programming. How can you, a Java Programmer take advantage of that fact to do your day-to-day task better like how do you sort a Map by values in Java using lambda expressions and Stream API. That's what you are going to learn in this article. It will serve two purposes, first, it will tell you a new way to sort a Map by values in Java, and, second and more important it will introduce you to essential Java 8 features like Lambda Expression and Streams, which every Java Programmer should learn.

5 Essential Spring Boot Annotations with Examples - Tutorial

Annotations have completely changed the way you write Java code. It's now impossible to write any Java code without using annotations but that's for good. They provide a lot of value and that's why it's important for a Java developer to get familiar with essential annotations of the framework he or she is using. When I think about Java, some of the essential annotations which come to our mind are @Override, @SuppressWarning, and @Deprecated. Similarly, if you are using the Spring Boot framework, an extension of the Spring framework which aims to simplify the Java development with Spring, you will often end up using a couple of annotations like @SpringBootApplication or @EnableAutoConfiguration.

Monday, September 6, 2021

Top 20 Essential Java Interview Questions with Answers for Freshers with 1 to 2 years Experienced

If you are a grad looking for an internship position in a company that uses Java, or a fresher, just out from college and looking out for a Java development position, then this post is for you. I have attended, taken, and participated in different levels of Java interviews. I can say there is a vast difference between them, which is not surprising because you obviously want to ask different level questions based upon whether the candidate is fresher or experienced. Similarly, the problem at phone interviews, written tests, and face-to-face interviews, keeping this in mind, and give you always have a limited amount of time before going for an interview, It's essential to prepare the right set of questions.

10 Advanced Programming and Development Books for Experienced Developers - Best of Lot

Hello guys, if you are looking for some advanced programming and development books to take your coding and software development skill to next level then you have come to the right place. Earlier, I have shared advanced courses in Java, Python, C++, and JavaScript and in this article, I am going to share some good books for the experienced programmer which can help them to become an expert. Learning never stops but once you become a professional programmer and spent a couple of years doing professional programming, you need to make some effort to reach the next level i.e. to become an expert programmer. Continuously doing the same stuff and not analyzing will not make you better. This is where these books can help you.

The Ultimate Guide of Lambda Expression of Java 8 - Example Tutorial

The Lambda expression is one of the most important features of Java 8 which has opened a whole new dimension of programming paradigm in Java. It is the feature which made the Functional Programming possible in Java because now you can pass the code to a function to execute as opposed to an object. You might be a bit surprised but if you look from a developer's point of view, it is nothing but a way to pass your code to a method in Java.

Sunday, September 5, 2021

4 Examples of Stream.collect() method in Java 8

Hello guys, you may know that Java 8 brought Stream API which supports a lot of functional programming operations like filtermapflatMap, reduce, and collect. In this article, you will learn about the collect() method. The collect() method of Stream class can be used to accumulate elements of any Stream into a Collection. In Java 8, you will often write code that converts a Collection like a List or Set to Stream and then applies some logic using functional programming methods like the filter, map, flatMap and then converts the result back to the Collection like a ListSetMap, or ConcurrentMap in Java.

Difference between List and ArrayList Reference Variables in Java? Example Tutorial

Someone who is just starting with Java programming language often has doubts about how we are storing an ArrayList object in List variable, what is the difference between List and ArrayList? Or why not just save the ArrayList object in the ArrayList variable just like we do for String, int, and other data types. Well, the main difference between List and ArrayList is that List is an interface while ArrayList is a class. Most importantly, it implements the List interface, which also means that ArrayList is a subtype of the List interface. In Java or any object-oriented language, the supertype of a variable can store an object of subtype.

How to Increasing Heap Size of Java application in JVM? Example Tutorial

Hello guys, if you are wondering how to change the heap size of the heap space of your Java application then you have come to the right place. In this article, I am going to tell you how to increase Java heap space so that your JVM will not crash using OutOfmemoryError. We have already seen how to increase heap memory in Maven and ANT and now we will learn how to increase heap size in Java, Eclipse, Tomcat, and WebSphere Server in a series of articles. Since all these are Java applications, once you know how to change heap space in Java, you can do that in any Java application, provided you know the right place, which is what we will see in this article.

Friday, September 3, 2021

The Ultimate Guide of Remote Debugging in Java using Eclipse IDE? Example Tutorial

The remote debugging of the Java program is an ultimate tool in the arsenal of a Java developer, which is often becoming the last and only tool to investigate a bug on a Java application running on the remote host like on a Linux server or Windows server. Almost all major Java IDE provides remote debugging like NetBeans, Eclipse, and IntelliJ IDEA, but I mostly use Eclipse for Java coding and so it's my preferred tool to remote debug a Java program. In order to set up remote debugging in Eclipse, you need to do a couple of tasks like you need to start your JVM with debugging parameters or arguments and then you need to create a "remote debug configuration" in Eclipse IDE itself.

How to Convert java.util.Date to LocalDate in Java 8 - Example Tutorial

Hello guys, once you move to Java 8, you will often find yourself working between old and new Date and Time API, as not all the libraries and systems you interact with will be using Java 8. One of the common tasks which arise from this situation is converting old Date to new LocalDate and that's what you will learn in this tutorial. There seems to be a couple of ways to convert a java.util.Date to java.time.LocalDate in Java 8, but which one is the best way? We'll figure it out in this article, but first, let's explore these different ways to convert a java.util.Date object to LocalDate in Java 8 code.

Thursday, September 2, 2021

How to Convert Stream to List, Set, or Collection in Java 8 - Example Tutorial

Hello guys, if you are following Java releases then you know that introduction of the Stream class is one f the most important addition in Java 8 as it makes processing bulk data really easy. Since data is the core part of any application and probably is the most important thing now than ever, a good knowledge of how to use Stream class effectively is important like how to work between Collections and Stream classes. If you have worked with Stream then you would have noticed that even though we can easily create a stream from a List and Set by using the stream() method added on java.uti.Collection interface, unfortunately, Stream class doesn't have a method to convert a Stream back to List or Set or any other data structure in Java.

Can you take training after passing OCMJEA 6 Exam (1Z0-897), Assignment(1Z0-865) and Essay (1Z0-866)?

Yes, you can take the training after passing the OCMJEA exam. Even though the training is a must to obtain the certification, You do not have to complete it before you give an exam. It is just listed as the first step to prepare well for your exam. If you have decent experience in core Java and enterprise Java, you can always complete the training when you are comfortable about it, but you must complete it to become an Oracle Certified Java Architect. In the last step of the exam, you need to submit a form containing the training detail to obtain credits for training.

How to parse String to LocalDate in Java 8 - DateTimeFormatter Example

From Java 8 onward, you are no longer dependent on the buggy and bulky SimpleDateFormat class to parse and format date Strings into real Date objects in Java e.g. java.util.Date. You can use the DateTimeFormatter class from java.time package for all your formatting and parsing need. You are also no longer required to use another buggy class java.util.Date if you are doing fresh development, but if you have to support legacy code then you can also easily convert LocalDate and LocalTime to java.util.Date or java.sql.Date. In this tutorial, we will learn about both parsing String to date in Java and formatting Date into String.

What is @Conditional annotations in Spring Framework? Example Tutorial

Hello guys, if you want to know what is @Conditional annotation in Spring Framework and how to use it then you have come to the right place. Earlier, I have shared free courses to learn Spring Framework and Spring Boot, and in this article, you'll learn what they are, how to use them with some beautiful examples. Spring 4.0 introduced the @Conditional annotation that is used for conditional checking for bean registration. This annotation offers more support than the @Profile annotation provided by the spring framework.