Distributing command-line Java applications traditionally involved building shadow JAR files, packaging ZIP archives, or writing operating system installers. JBang Catalogs revolutionize Java application...
One of the biggest advantages of JBang is that you don't give up rich IDE features like code auto-completion, refactoring, syntax highlighting, and interactive debugging when writing single-file Java scripts....
Both JShell and JBang were created to solve a long-standing complaint in the Java community: the boilerplate overhead required to quickly run Java code. However, while they sound similar, JShell and JBang...
JBang transforms Java into a scriptable language with zero build tool setup required. Whether you are scripting CI/CD pipelines, prototyping REST APIs, or building CLI tools, this reference cheatsheet...
Over time, local Maven repositories (located by default at ~/.m2/repository) accumulate gigabytes of cached JARs, POMs, and dependencies. Inspecting or filtering these cached artifacts using traditional...
For years, developers turned to Python or Bash scripts for automation tasks because Java felt too verbose—requiring full project structures, pom.xml configurations, and manual compilation. JBang completely...
MapStruct is a powerful Java annotation processor that simplifies the mapping between Java bean types. In this advanced tutorial, updated for MapStruct 1.6.3.Final, we will explore several advanced features...
Mapping Java Enums between database entities, domain models, and external API DTOs is a routine necessity in enterprise applications. While MapStruct automatically maps enum constants with matching names...
Mapping collections—such as List, Set, and Map—between domain entities and Data Transfer Objects (DTOs) is a routine task in Java applications. MapStruct simplifies this process by automatically generating...
MapStruct is one of the most popular Java libraries for generating high-performance, type-safe bean mappers at compile time. However, because MapStruct performs strict validation during compilation, a...
Java KeyStores provide a secure mechanism to store cryptographic keys, X.509 certificates, and trusted CA certificates. They are widely used by Java application servers like WildFly, Spring Boot, and JBoss...
The error java.lang.OutOfMemoryError: Metaspace indicates that you have exhausted an area of the JVM which serves as a registry for your application's Class Metadata. This article is a step-by-step guide...
Measure Java method execution time without code changes using Byteman or Spring AOP. Identify bottlenecks effortlessly with script-based tracing or AspectJ. Optimize performance with precise timing insights....
This article goes through the most common Java OutOfMemory Error, which happens when you saturate the Java Heap Memory. Within this article, we will show how to fix this error depending on whether you...
Java 18 is finally available for download! In this article we will learn some of the most interesting Enhancement Proposals (JEPs) which are now available in the JDK. Firstly, let’s download the Java 18...
This article discusses which are the best strategies to tune a Linux machine where you are running Java applications. We will first cover the best tools you can use for your analysis and then we will pinpoint...
An OutOfMemoryError: Direct buffer memory is a common error that Java developers encounter when working with applications that use large amounts of direct memory. Direct memory is allocated outside of...
Lombok is a popular Java library that aims to reduce boilerplate code by providing annotations that generate getters, setters, constructors, and other commonly used methods automatically during the compilation...
LDAP is commonly used in Security realms as a source of authentication and authorization information. This tutorial will teach you two simple strategies for starting an LDAP Server in minutes in order...
When it comes to parsing PDF files in Java, two popular libraries stand out: Apache Tika and Apache PDFBox. Both libraries provide powerful features for working with PDF documents, but they have different...
The heap size of Java applications significantly impacts memory utilization and, consequently, performance aspects such as garbage collection cycles and compressed pointers. Tuning the heap size becomes...
The java.nio.file package provides the WatchService API for monitoring changes to the file system. This tutorial will guide you through using WatchService to detect events like file creation, modification,...
Calling all Java enthusiasts! I’m excited to share that my latest tiny ebook is now live—a concise reference guide covering all the top features in Java from version 8 to the upcoming version 22! 🚀 Let’s...
Are you going for a Java Interview ? This article contains a list of Interview Questions which are covering modern aspects of Java, such as Functional programming, Stream API, new IO API and much more....
In this article we will go through a common issue that you can face when compiling and running applications with Maven. The syntom of this issue is that Maven is using the wrong version during the execution....
Virtual threads, also known as project Loom, are a new feature available in Java 21 that aims to provide lightweight, efficient, and scalable concurrency. They are designed to improve the performance and...
Lambda expressions in Java are a concise way to represent anonymous functions or “function literals.” They are primarily used to implement functional interfaces, which are interfaces with a single abstract...
Structured concurrency (JEP 453) is a method of organizing concurrent programming in a way that maintains the relationship between tasks and subtasks. This approach aims to make concurrent code more readable,...
The EnumMap and EnumSet are specialized implementations in Java that are optimized for working with Enum keys and Enum values, respectively. In this article we will learn how to use them and which are...
In this post I will keep some useful Java hacks and one-liners which are useful in every day programming Multiple Each Item in a List by 2 Sum a List of Numbers Verify if String exists in a List Create...
This article is whirlwind tour across the Java Flight Recorder (JFR) and the Java Mission Control (JMC) suite. At the end of it, you will be able to monitor, collect diagnostic data and profile any running...
This article will introduce you to SpotBugs utility project that can assist you to spot Java “bug patterns” in your code which are likely to turn into runtime bugs. Firstly, let’s see how SpotBugs works....
The Java 11 HttpClient API provides a lot of configuration options that you can use to tune its performance. In this tutorial, we will explore some of the most important ones. Connection pooling is a technique...
Java 21 introduces two language core features: Unnamed Java Classes and a new launch protocol which allows running Java classes in a simpler format. In this article we will cover in detail these new features...
The java.net.SocketException Connection reset is a common Runtime error within Java applications. This tutorial delves into its occurrences, diagnostic steps, and effective solutions. A java.net.SocketException...
Hidden classes ( available since Java 15 ) allow developers to define classes that cannot be directly accessed by other classes in the same program. These classes are designed for use by frameworks that...
This article shows how to fix the compilation issue that you can hit when the target Java release specified in your Maven configuration does not match the version of Java installed on your system. For...
The error “java.lang.OutOfMemoryError: GC overhead limit exceeded” is fairly common for old JDK (mostly JDK 1.6 and JDK 1.7) . Let’see how to solve it. According to the JDK Troubleshooting guide, the “java.lang.OutOfMemoryError:...
This article continues our learning through the Java Mission Control (JMC) tool. Within it, we will learn how to run JMC as standalone application or as Eclipse IDE plugin. Firstly, if you are new to Java...
One critical tool in diagnosing memory-related issues is the Heap dump, a snapshot of an application’s memory at a particular point in time. However, as applications become larger and more intricate, heap...
The java.lang.NoClassDefFoundError: javax/xml/bind/JAXBException error (or other javax.xml.bind classes) typically arises due to missing JAXB API in your Classpath or Runtime. Here’s how to resolve it....
This article will guide you in troubleshooting Java application by analysing a Thread dump with the instruments available in the JDK. We will also learn some tools to simplify our analysis. Java has mechanisms...
To troubleshoot a Java application it is common to analyze both Heap Dumps and Thread Dumps. In this article we will learn how to extract a Thread dump from an Heap Dump with some freely available tools...
When working with Java, it’s often necessary to convert data structures to and from different formats, especially when dealing with JSON data. Fortunately, libraries like Jackson provide robust support...
A heap dump is a snapshot of the Java Virtual Machine’s memory, capturing the state of objects and their relationships. Analyzing heap dumps aids in diagnosing memory-related issues, identifying memory...
In this tutorial, we will learn how to capture a thread dump in Java using different methods depending on the operating system and the environment in which the Java application is running. A thread dump...
This article will discuss the Java ZGC garbage collector and how you can configure and use it to meet your needs in modern Java applications. The Java ZGC is a scalable low latency garbage collector that...
There are over 70 Java-based open source machine learning projects listed on the MLOSS.org website, and probably many more unlisted projects live at university servers, GitHub, or Bitbucket. In this article,...
This article is an introduction to gRPC framework which allows to connect services across data centers using high performance Remote Procedure Calls (RPC). To learn the building blocks of this framework,...
This article is a whirlwind tour of AtlasMap Data transformation API and User Interface. We will learn how to use its editor to define mapping rules and how to use them in a sample Java Integration project....
Sorting arrays efficiently is crucial for optimizing performance in Java applications. With numerous sorting algorithms and built-in methods available, it’s essential to identify the most efficient approach...
Java 17 is soon becoming the minimal JDK version for top frameworks such Spring Boot. Selecting the right OpenJDK 17 image for your projects is crucial. This tutorial aims to introduce and test various...
This tutorial demonstrates how to convert a JSON string into a Java Map using Jackson’s ObjectMapper. We will show a basic Java main Class to convert a sample JSON String. Then, we will simplify the classpath...
Java records and Lombok are both tools that aim to reduce boilerplate code in Java, but they have different approaches and use cases. In this article we will compare them to understand which is the perfect...
In this tutorial, we will explore how to convert a PDF document into raw text using the Apache PDFBox library in Java. This process can be particularly useful for applications that need to analyze or summarize...
This step-by-step guide will show you how to create a minimal Java LDAP Client to test the connection to an LDAP Server and show the LDAP tree using a graphical interface. We will use Docker to trigger...
Java lacks direct support for default parameter values as seen in some other programming languages. However, there are several techniques and patterns you can utilize to achieve similar functionality....
In this comprehensive guide, we uncover the diverse techniques to init an array in Java, discussing basic and advanced approaches. Whether you’re diving into static or dynamic array creation, Arrays.copy...
If you encounter javax.net.ssl.SSLHandshakeException while developing or deploying Java applications on WildFly, Spring Boot, Quarkus, or microservices, it often indicates a mismatch between your client...
If you’re a developer who has worked with web APIs, you might have come across the HTTP 415 “Unsupported Media Type” error. This error occurs when the server doesn’t support the media type that’s being...
The finally block in Java is used to define a section of code that will always be executed, regardless of whether an exception is thrown or caught. However, there are certain conditions under which the...
When it comes to consuming HTTP resources in Java applications, Apache HTTP Client is a popular choice for developers due to its ease of use, flexibility, and robustness. In this article, we will explore...
Scenario: You are not able to start the Java Virtual Machine. The JVM exits and prints the error message “Could not reserve enough space for object heap” on the Console Facts: Upon start, the JVM prints...
In this article we will discuss on how to migrate Java applications from Java 8 to Java 17 using the OpenRewrite migration plugin. At the end of this tutorial, you will learn which are most common challenges...
When working with Java, it’s common to encounter situations where you need to handle multiple exceptions. Fortunately, Java provides a simple and efficient way to do this using the catch block. In this...
Do you need to read a File into a String in Java ? This article will show two simple ways to achieve it. By the end of it, you will also learn the differences between each solution. The first solution,...
When using WildFly or JBoss EAP, the JAXB implementation is defined by the following specification in module.xml: In order to check the actual JAXB implementation, you can just create a new Instance of...
There are several ways to create an HTTP client in Java. In this tutorial, we will explore five different options for creating an HTTP client in Java, ranging from low-level libraries to high-level frameworks....
This article will teach you what is the usage of the HeapDumpOnOutOfMemoryError JVM parameter and how to configure it on an application server such as JBoss EAP or WildFly. The JVM parameter “-XX:+HeapDumpOnOutOfMemoryError”...
In Java, working with collections like lists is fundamental. Often, you’ll need to convert objects or records into lists for various purposes. In this tutorial, we’ll explore different approaches to create...
In this brief article we will outline three JVM configuration parameters you can add to the JVM to handle a scenario when your application issues an OutOfMemoryError. The OutOfMemoryError: Java heap space...
Scenario: Your application log displays the error message “Too many Open Files“. As a result, application requests are failing and you need to restart the application. In some cases, you also need to reboot...
This article describes how to fix the error “java.lang.OutOfMemoryError: Compressed class space error” which is an error that can occur on a 64-bit platform. Starting with Java 1.8, loaded classes are...
The Java SecurityManager, a veteran of the platform since JDK 1.0, has been officially deprecated for removal. Besides, Jakarta EE 11 removes support for running with a SecurityManager. This article explores...
JSONPath is a powerful tool for querying JSON data, similar to XPath for XML. Combining JSONPath with Jackson, a popular Java library for JSON processing, allows for advanced mapping of JSON structures...