Eric Martin

Baeldung on Java

All
Java (72)
Java String (56)
Java IO (44)
Testing (43)
Spring Boot (43)
Core Java (38)
Persistence (30)
Java Numbers (28)
Spring Data (27)
Java List (27)
Java Concurrency (27)
Java Array (27)
Java Map (26)
Spring (25)
JVM (24)
Data (23)
Algorithms (23)
JPA (21)
Security (18)
Java Collections (18)
Maven (15)
JSON (15)
DevOps (14)
Spring Security (13)
NoSQL (13)
Java Streams (13)
Java Dates (13)
HTTP Client-Side (12)
REST (11)
Cloud (10)
Artificial Intelligence (10)
Architecture (10)
Logging (9)
Spring MVC (8)
Spring AI (8)
Networking (8)
Jackson (8)
IDE (8)
Spring Web (7)
Spring Cloud (7)
Groovy (7)
Gradle (7)
Jakarta EE (6)
Web Services (4)
Reactive (4)
Spring WebFlux (3)
Spring Persistence (3)
Java Web (3)
Docker (3)
XML (2)

Reuse Embedded Kafka Broker in Multiple Test Classes

Learn how to reuse an embedded Kafka broker in multiple test classes to speed up integration tests.

Tool to Analyze Offline Java Heap Dumps

Filed under Java

Explore two different memory analyzers to demonstrate how we analyze the Java heap memory via an offline heap dump file.

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Resolving JSONException: JSONObject text must begin with ‘{‘ in Java

Filed under JSON

Explore why the ‘JSONObject text must begin with ‘{‘ at character 0’ exception occurs, what it means, and how to resolve it, with clear examples.

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Guide to Maven Toolchains

Filed under Maven

Explore Maven Toolchains and how they let us define specific tool versions for our builds.

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How to Randomly Get a Key, a Value, or an Entry From a HashMap in Java

Filed under Java Map

Explore different ways to randomly retrieve data from a HashMap in Java.

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How to Query JPA LocalDateTime Field With a LocalDate Value

Filed under Java Dates, JPA

Learn how to query LocalDateTime fields using a LocalDate value in JPA using simple range queries, JPQL functions, and dynamic Criteria API queries.

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Set the Null Value for a Target Property in MapStruct

Filed under Java

Learn different ways to always set a specific object field to null using MapStruct.

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Bind Custom Validation Message in Spring

Filed under Spring Boot

Learn about Spring Boot’s validation message system, how to configure it effectively, streamline error handling, and make message management more intuitive.

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Order of Configuration in Spring Boot

Filed under Spring Boot

Explore the order of configuration in Spring Boot as an essential tool for building predictable and maintainable applications.

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Baeldung on Linux

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Administration (80)
Scripting (76)
Files (72)
File Editing (48)
Filesystems (29)
File Searching (25)
Text Processing (23)
Processes (23)
Installation (18)
Web (15)
File Viewing (12)
Security (10)
Package Management (7)
Docker (7)
User Administration (6)
Search (6)
Networking (6)
Boot Process (5)
Network Configuration (4)
File Permissions (4)
File Conversion (4)
File Compression (4)
Network Monitoring (3)
Building (3)
Service Management (1)
File Transfer (1)

How Do File Permissions Work for the Root User

Filed under File Permissions

Learn how file permissions work for the root user, how root can override them, and discover scenarios where even the root is restricted.

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What Are the Differences Between [0-9], [[:digit:]] and \d

Filed under File Searching, Scripting

Explore these expressions, compare them, discuss how they behave differently under various conditions, and provide practical Linux examples to show their differences

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Identifying the Window Manager and Desktop Environment in Linux

Filed under Administration

Break down the differences between a Window Manager and a Desktop Environment then discuss different methods to identify each.

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Dual Boot Ubuntu Alongside macOS

Filed under Boot Process

Learn how to install Ubuntu along with macOS on Intel-based Macs.

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How to Tell if a Linux Machine Supports AVX/AVX2 Instructions

Filed under Administration

Learn how to tell if a Linux machine supports Advanced Vector Extensions (AVX) and its extension, AVX2 instructions.

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What Is a Bootloader in Linux?

Filed under Boot Process

Learn about what a bootloader is and how it works to load and initialize an operating system

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What’s the Difference Between find . and find . -print

Filed under File Searching

Explore difference between find . and find . -print including their historical context and subtle differences

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How to Uninstall GNOME Stock Applications

Filed under Installation

Learn how to remove the stock GNOME apps from several distributions, using their respective package manager

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Executable Cannot Be Found Although It’s in the $PATH in Alpine Docker

Filed under Docker

Explore the common “executable not found” error in Alpine Docker containers and how to fix it, including causes like missing libraries and mismatched architectures.

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Baeldung on Scala

All
Testing (1)
Scala Web (1)
Scala Strings (1)

Testing With Gatling Using Scala

Filed under Scala Web, Testing

See how to easily write scenarios to performance test your REST application using Gatling with Scala.

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Generate Secure Random Passwords in Scala

Filed under Scala Strings

Learn how to generate secure random passwords with various criteria.

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Baeldung on Computer Science

All
Machine Learning (17)
Algorithms (15)
Programming (13)
Networking (12)
Security (9)
OS (9)
Artificial Intelligence (7)
Searching (6)
Latex (6)
Math and Logic (5)
Data Structures (5)
Core Concepts (5)
Deep Learning (4)
Web (3)
Sorting (3)
Software Architecture (3)
Trees (2)
Graphs (2)
Graph Traversal (2)
Path Finding (1)
Concurrency (1)
Computer Vision (1)

How to Start Building an Operating System

Filed under OS

Examine resources that apply to all operating system development endeavors and explore learning paths based on specific operating system concepts and programming languages.

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How to Calculate the Number of Tag, Index, and Offset Bits of Different Caches

Filed under Core Concepts

Learn how to calculate the allocation of tag, index, and offset bits in different cache architectures.

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What Is Prompt Engineering?

Filed under Artificial Intelligence

Learn about prompt engineering, its importance, various prompt techniques, and components.

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Introduction to the Fetch-Execute Cycle

Filed under OS

Explore the Fetch-Execute cycle and its stages in detail.

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How to Implement a Queue Using Two Stacks?

Filed under Data Structures

Learn two approaches to simulating a FIFO queue using two LIFO stacks.

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WaveNet Speech Synthesis

Filed under Deep Learning

Study speech synthesis using the WaveNet model

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Detecting Syllables in a Word

Filed under Artificial Intelligence

Explore several approaches to finding syllables in a word, which is an important task in natural language processing (NLP).

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SEO: Off-Page vs. On-Page Techniques

Filed under Web

On-page SEO focuses on optimizing individual web pages, while off-page SEO focuses on improving a website’s overall quality

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Baeldung on Kotlin

All
Kotlin Collections (3)
Kotlin Strings (2)
Kotlin Numbers (2)
Kotlin Classes and Objects (2)
Kotlin Arrays (2)
Security (1)
Kotlin IO (1)
Kotlin Functions (1)
Kotlin (1)
HTTP Client-Side (1)

Resolving Kotlin Error: “Primary constructor call expected”

Filed under Kotlin Classes and Objects

Explore various approaches to fixing this error, illustrating each with problematic code examples, their solutions, unit tests, and detailed explanations.

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Kotlin Application Deployment With Docker and Kubernetes

Filed under Kotlin

Learn to deploy a simple Kotlin application to Kubernetes (K8s) using Docker and Docker Hub.

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Spring Security JWT With Kotlin

Filed under Security

See a Spring Boot application example with tests to use JWT and secured endpoints.

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Convert a Data Class to ByteBuffer in Kotlin

Filed under Kotlin Classes and Objects

Learn how to convert a Kotlin data class to a ByteBuffer using different forms of serialization

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Rename a File in Kotlin

Filed under Kotlin IO

Learn how to use the built-in method exposed by the File class or use the Files class from the Java NIO package to rename files in Kotlin

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Getting Binary Representation of Int in Kotlin

Filed under Kotlin Numbers

Explore the methods available in Kotlin to get the binary representation of integers.

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Check if a Number Can Be Expressed as Sum of Two Prime Numbers in Kotlin

Filed under Kotlin Numbers

Explore multiple approaches to checking if a number can be expressed as the sum of two prime numbers.

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Convert String Array to Int Array in Kotlin

Filed under Kotlin Arrays, Kotlin Strings

Learn to convert a String array to an Int array in Kotlin and how to handle potential exceptions.

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Baeldung on Ops

All
Docker (30)
Kubernetes (26)
Jenkins (6)
Git (6)
Cloud (3)
Logging (1)
DevOps (1)

How to Change a Docker Container’s MTU

Filed under Docker

By keeping container MTU settings in sync with the host and the broader network infrastructure, teams can minimize packet loss, avoid fragmentation, and maintain consistent performance, even in environments that involve tunnels, VPNs, or overlay networks.

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Sticky Session on Kubernetes Cluster

Filed under Kubernetes

Explore how sticky sessions work in Kubernetes, why they are important for stateful applications, and the different ways they can be implemented.

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Monitor Jenkins Build Status in a GitHub Repository

Filed under Git, Jenkins

Learn two efficient methods for tracking Jenkins build status directly within GitHub.

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Create Namespace Using Helm Templates

Filed under Kubernetes

Learn how to create a namespace using Helm templates, ensuring consistency and reusability in your Kubernetes deployments

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Passing Environment Variables to a Vue App at Runtime

Filed under DevOps

Walk through a practical approach to dynamically injecting environment variables and configuring the app to read them effectively.

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Understanding backoffLimit in Kubernetes Jobs

Filed under Kubernetes

Explore backoffLimit, its importance, practical applications, how to configure it effectively, and tips for balancing reliability with resource efficiency.

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Load a Docker Image From a Tar File

Filed under Docker

Learn how to save Docker images into tar files and load them back in

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Guide to Setup Jenkins on Kubernetes

Filed under Jenkins, Kubernetes

Deploying Jenkins on Kubernetes offers a robust, scalable solution for automating CI/CD pipelines, enabling seamless integration and delivery across software projects.

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Docker Interactive Mode After Executing Script

Filed under Docker

Learn how to run a script inside a Docker container after its creation and access to a shell terminal

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Baeldung on SQL

All
SQL Queries (10)
Database Concepts (4)
SQL Tables (3)
SQL Views (2)
Security (1)
SQL Joins (1)
SQL Basics (1)
Database Access (1)
DML (1)

Update Multiple Rows With Different Values With Single Query

Filed under SQL Queries

Explore how to update multiple rows with different values, depending on the value of existing columns

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Generate SQL Insert Script From Excel Worksheet

Filed under SQL Queries

Explore methods for generating SQL INSERT scripts from an Excel worksheet and best practices for ensuring a smooth execution process.

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SQL injection that gets around mysql_real_escape_string()

Filed under Security

Review some obscure corner cases that enable malicious inputs to slip past mysql_real_escape_string().

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SQL Query for Calculating a Rolling 7-Day Average

Filed under SQL Queries, SQL Views

Discuss a general approach to calculating a 7-day rolling average, including indexed views in MSSQL Server, materialized views in MySQL, and materialized views with refresh in PostgreSQL.

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