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Java Records in JPA/Spring Data: Challenges and Usecases

Java records cannot be used as the replacement for JPA entities because they restrict the byte code manipulation, generally required by frameworks to work.

Java Array vs. ArrayList: Comparison and Conversion

Java ArrayList is part of the collection framework and implementation of resizable array data structure. Learn when to use array and arraylist.

Java ArrayList Length and Size

Java ArrayList does not publicly expose the length of the backing array, and only the count of the stored elements can be retrieved using its size() method.

Java ArrayList Sort: Ascending and Descending Order

Learn to sort Java ArrayList in ascending and descending order using ArrayList.sort(), Collections.sort(), Comparator interface and Java 8 Streams.

Java – Convert Decimal to Hexadecimal and Vice-versa

Learn the conversion of decimal to hexadecimal and using converting hex to decimal in Java using the built-in APIs and custom methods.

Spring @PathVariable and @RequestParam

Learn about Spring @PathVariable and @RequestParam annotations and compare them with Jakarta’s @PathParam and @QueryParam annotations.

Spring Boot RestClient (with Examples)

Starting Spring Framework 6.1 and Sring Boot 3.2, we can use the Spring RestClient for performing HTTP requests using a fluent and synchronous API. The RestClient works over the underlying HTTP client libraries such the JDK HttpClient, Apache HttpComponents, and others. As the name suggests, RestClient offers the fluent API design …

Creating a Jasper Report with Spring Boot

Learn to create Jasper reports in a Spring boot application, step by step, by configuring JasperReport library, loading the report templates, fill the data into reports and finally export the filled reports into a variety of formats.

Java Record Patterns and Pattern Matching

Learn what is pattern, and record patterns in detail along with how they help in pattern matching for instanceof and switch statements.

Java 21 Unnamed Classes and Instance Main Methods

Since Java 21, we can use unnamed classes and instance main methods that allow us to bootstrap a class with minimal syntax.

Java 21 Sequenced Collections

The new sequenced collection interfaces allow adding, retrieving, and removing elements at either end of the collection, along with a reverse-ordered view of it.

Difference between Sourcepath, Classpath and Buildpath

Learn the differences between Sourcepath, Classpath and Buildpath and how they contribute to an application’s development, build and deployment phases.

Java 21 Features (LTS): Practical Examples and Insights

This article discusses the new developer features in Java 21 including Virtual Threads, Unnamed classes, Sequenced Collections and Record Patterns.

Java Interview Puzzles and Coding Exercises

These Java puzzles and their solutions will help in the next Java Interview. The key to solving these puzzles is to come up with an efficient algorithm. and write clean code.

Python Pandas 101: A Beginners Guide

Learn to get started with Python Pandas library and using Pandas for data visualization, manipulation including advantages and limitations.

Spring Boot and Kafka Streams Example

Learn to create a Kafka Streams application using Spring Boot. Also, learn about Topology and Processor and unit test the topology design.

Spring CrudRepository and ListCrudRepository Examples

Learn to use Spring CrudRepository and ListCrudRepository interfaces, their differences and the changes made in Spring Data 3.0 with examples.

Spring Boot File Upload REST API Example

Learn to write a REST API in Spring Boot that can handle single file and multiple file uploads. Also learn to validate the file sizes and types.

Setting Java Version used by Maven Compiler

Learn to configure the Java compiler version in a Maven project and a Spring boot application using Maven as a build tool.

Spring Boot Logging Levels Example

Learn to configure the logging levels for different packages and classes in a Spring boot application using properties, YAML and XML configurations.

Spring Boot Role-Based Authentication with AWS Cognito

Spring Security framework supports a wide range of authentication models, and in this tutorial, we will cover OAuth2 authentication using Amazon Cognito. We will walk through a step-by-step guide from creating the user pool in the AWS, adding the app client, and configuring it in the Spring Boot application. 1. …

Spring Boot REST API Example – Step-by-Step Guide

Learn to build REST APIs in a Spring boot application with request validation, error handling, testing and API documentation with examples.

Spring Boot and Vaadin CRUD Example

Vaadin is a Java framework that simplifies front-end development by providing a rich set of reusable UI components and layouts. In this Spring Boot and Vaadin tutorial, we will explore the process of developing a basic CRUD application. 1. Goals Our goal is to construct a user interface that includes …

Apache Kafka using Spring Boot

Learn to configure Spring boot application and Apache Kafka Producer, and Consumer, handle Kafka errors and retry in case of failures.

Spring Boot Security Role-based Authorization

Learn the core concepts of configuring role-based authorization in Spring Security 6 and implementing authorization in a Spring Boot application.

TypeScript Optional and Default Parameters

In TypeScript, the default and optional parameters provide a convenient way to APIs with variable number of arguments with sensible defaults.

TypeScript Array slice()

Typescript array slicing creates a new array containing shallow copies of the selected elements from the source array without modifying the source array.

Spring Boot REST API for Long-Running Tasks

Learn to design and implement a Spring Boot REST API that accepts long-running tasks and publishes the execution progress to a Kafka topic.

Spring Boot @KafkaListener and @KafkaHandler Example

Spring @KafkaListener and @KafkaHandler annotations provide convenient ways to consume and handle messages from Kafka topics.

Using Spring KafkaAdmin to Create New Topics Programmatically

Learn to configure KafkaAdmin with custom properties, and create new topics in the Kafka cluster using AdminClient.createTopics() with example.

Using KafkaTemplate with Spring Boot

Learn the basics of KafkaTemplate, configure KafkaTemplate with custom properties, and configure producer and consumer factories with examples.

[Solved] This version of ChromeDriver only supports Chrome version

Learn to fix the selenium WebDriver error “This version of ChromeDriver only supports Chrome version” during UI testing.

Top 5 View Template Engines for Spring

Learn about top 5 template engines for Spring MV applications, comparing their features and setup process, to make more informed decisions.

[Solved] Maven – Fatal error compiling: invalid target release

Learn to fix Maven invalid target release error which indicates that Java versions used in Maven and in the application are not compatible.

OpenAI ChatGPT APIs using Spring Boot

Learn to call OpenAI ChatGPT APIs in Spring Boot RestTemplate or WebClient with an example. Also, log the requests and responses for debugging.

Kafka Single and Multi-Node Clusters using Docker Compose

Learn to configure, modify and deploy a single-node and a multi-node setup of Apache Kafka using Docker Compose. Also, learn to create topics.

Spring Boot App Automatically Closes with Exit Code 0

Learn the most common solutions for the Spring boot application closing automatically after start, with exit code 0 and no exceptions logs.

Spring Boot @ServiceConnection

Since Spring Boot 3.1, @ServiceConnection is used to provide connection details to a remote service that takes precedence over details in the properties file.

Stream Processing with Redis and Spring Boot Data

Learn to use Redis Streams in a Spring Boot application to implement simple, in-memory and real-time stream processing of messages/events.

Spring Boot Docker Compose Example

Learn to use Spring boot docker compose module, customize the compose file and container lifecycle with an example.

Spring Cloud AWS: Read, Upload, Delete a File from S3

Learn the fundamentals of working with S3 buckets and objects using Spring Cloud AWS library and its S3Client and S3Template classes.

Java Map computeIfAbsent()

The Map.computeIfAbsent() method computes the mapped value for a key using a mapping function if the specified key does not exist in the Map or is mapped to a null value. It has been added as the default method in the Map interface in Java 8. 1. When to Use the computeIfAbsent() …

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Lokesh Gupta

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