This article shows how to create or scaffold a Gradle + Quarkus JAX-RS hello world project, which creates a /hello endpoint and returns a string. Technologies used: Quarkus 1.11.0 Gradle 6.7 Maven 3.6.3 Java 11 Topics Creating a new Gradle + Quartus project Gradle + Quarkus Project Structure Quarkus and build.gradle Quarkus Dependencies (runtimeClasspath) Quarkus […]
This article shows how to use the quarkus-maven-plugin to create or scaffold a Maven + Quarkus JAX-RS hello world project. Technologies used: Quarkus 1.11.0 Maven 3.6.3 Java 11 Topics Creating a new Maven + Quartus project Maven + Quarkus Project Structure Quarkus and pom.xml Quarkus Dependencies Quarkus JAX-RX endpoint Quarkus and Dockerfile Run Quarkus in […]
This article shows how to use a keyboard shortcut to access the parent folder or any item or folder on macOS. 1. Go to the parent folder. (Command + Up Arrow) In Finder, we can press Command + ↑ to access the parent folder of any item or folder. 1.1 For example, in Finder, this […]
This article shows how to use a keyboard shortcut to go to a specified folder on macOS. 1. Go to a specified folder. (Shift + Command + G) In Finder, there is no explorer to type the path you want to go. To fix it, we can press Shift + Command + G together to […]
This article shows you how to enable Gmail dark mode or dark theme on desktop, Android, and iPhone or iPad (macOS). Topics Gmail Dark Mode on Desktop Gmail Dark Mode on Android Gmail Dark Mode on iPhone and iPad (macOS) 1. Gmail Dark Mode on Desktop PC. 1.1 Any web browsers, log in the Gmail, […]
Try to install VirtualBox on macOS, and hits the error "The Installation failed."? P.S Tested with VirtualBox 6.1 and macOS Big Sur 11.1 Solution 1.1 Desktop, top menu, clicks Apple icon -> System Preferences… 1.2 Clicks on the Security & Privacy icon. 1.3 Clicks on the left-bottom lock icon, type password to unlock it. 1.4 […]
With XSLT(Extensible Stylesheet Language Transformations), we can transform XML documents into other formats such as HTML. Table of contents 1. DOM Parser and Transformer 2. DOM example: XML + XSLT = HTML format 3. Download Source Code 4. References P.S Tested with Java 11 1. DOM Parser and Transformer We can use the TransformerFactory to […]
By default, Homebrew will install all packages in the directory /usr/local/Cellar/, and also creates symbolic links at /usr/local/opt/ and /usr/local/bin/ (for executable files). Terminal /usr/local/Cellar/ /usr/local/opt/ /usr/local/bin/ Terminal % brew -v Homebrew 2.7.2 Homebrew/homebrew-core (git revision 3c379; last commit 2021-01-11) Homebrew/homebrew-cask (git revision 40d45; last commit 2021-01-11) P.S Tested with Homebrew 2.7.2 and macOS Big […]
By default, the Quarkus application starts on HTTP port 8080. Terminal $ mvn compile quarkus:dev __ ____ __ _____ ___ __ ____ ______ –/ __ \/ / / / _ | / _ \/ //_/ / / / __/ -/ /_/ / /_/ / __ |/ , _/ ,< / /_/ /\ \ –\___\_\____/_/ |_/_/|_/_/|_|\____/___/ […]
In this article, we’ll learn how to read and write Microsoft Word with the help of Apache POI library. Topics Apache POI – HWPF and XWPF Apache POI dependencies Create a word document Working with Paragraphs, Fonts, and Page breaks Document Header and Footer Add Image Create a table Read and parse document, paragraph, and […]
Note The BufferedReader reads characters; while the InputStream is a stream of bytes. The BufferedReader can’t read the InputStream directly; So, we need to use an adapter like InputStreamReader to convert bytes to characters format. For example: // BufferedReader -> InputStreamReader -> InputStream BufferedReader br = new BufferedReader( new InputStreamReader(inputStream, StandardCharsets.UTF_8)); 1. Reads a file […]
This article shows different ways to initialize HashMap in Java. Initialize a HashMap (Standard) Collections.singletonMap Java 9 Map.of Java 9 Map.ofEntries Create a function to return a Map Static Initializer Java 8, Stream of SimpleEntry Conclusion After initialized a HashMap, the result is either a mutable map or an immutable map: Mutable map – It […]
The Files.find API is available since Java 8. It searches or finds files from a file tree quickly. Topics Files.find() method signature Find files by filename Find files by file size Find files by last modified time In the old days, we always use an error-prone recursive loop to walk a file tree. This Java […]
This article shows how to get the file extension of a file in Java. Topics Get file extension normal Get file extension strict Get file extension hardcode Apache Common IO – FilenameUtils Path: /path/foo.txt -> File Extension: txt Path: . -> File Extension: Path: .. -> File Extension: Path: /path/run.exe -> File Extension: exe Path: […]
In this article, we will demonstrate an integration test where we have to persist the entities with mocked auditing date fields when JPA Auditing is enabled. Technologies used: Spring Boot 2.4.0 Spring 5.3.1 JUnit Jupiter 5.7.0 Tomcat embed 9.0.39 Java 8 1. Project Dependencies pom.xml <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-data-jpa</artifactId> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>com.h2database</groupId> […]
The Alphanumericals are a combination of alphabetical [a-zA-Z] and numerical [0-9] characters, a total of 62 characters, and we can use regex [a-zA-Z0-9]+ to matches alphanumeric characters. If we want regex matches non-alphanumeric characters, prefix it with a negate symbol ^, meaning we want any characters that are not alphanumeric. ^[^a-zA-Z0-9]+$ Regex explanation ^ # […]
The Alphanumericals are a combination of alphabetical [a-zA-Z] and numerical [0-9] characters, 62 characters. We can use below regex to match alphanumeric characters: ^[a-zA-Z0-9]+$ Regex explanation ^ # start string [a-z] # lowercase letters from a to z [A-Z] # uppercase letters from A to Z [0-9] # digits from 0 to 9 + # […]
This article shows how to use Spring Boot to create REST endpoints to run the background jobs managed by the JobRunr. Tested with: Spring Boot 2.3.12.RELEASE JobRunr 3.1.2 Maven 3 1. Directory Structure. A standard Maven project structure. 2. Project Dependencies. We need a single jobrunr-spring-boot-starter to integrate Spring Boot web and JobRunr. pom.xml <!– […]
Java 15 reached General Availability on 15 September 2020, download Java 15 here. Java 15 features. 1. JEP 339: Edwards-Curve Digital Signature Algorithm (EdDSA) 2. JEP 360: Sealed Classes (Preview) 3. JEP 371: Hidden Classes 4. JEP 372: Remove the Nashorn JavaScript Engine 5. JEP 373: Reimplement the Legacy DatagramSocket API 6. JEP 374: Disable […]
Run a simple java command on Ubuntu and hits the below errors: Terminal $ java -version bash: /usr/bin/java: cannot execute binary file: Exec format error P.S Tested with Java 15 and Ubuntu 20 1. Problem – Download the wrong JDK build The error Exec format error means we download the wrong JDK build for a […]
In Java, we can use the following code snippets to get the path of a running JAR file. // static String jarPath = ClassName.class .getProtectionDomain() .getCodeSource() .getLocation() .toURI() .getPath(); // non-static String jarPath = getClass() .getProtectionDomain() .getCodeSource() .getLocation() .toURI() .getPath(); Sample output. Terminal /home/mkyong/projects/core-java/java-io/target/java-io.jar 1. Get the path of running JAR 1.1 Create an executable […]
This article shows how to convert a File to a Path in Java. java.io.File => java.nio.file.Path // Convert File to Path File file = new File("/home/mkyong/test/file.txt"); Path path = file.toPath(); java.nio.file.Path => java.io.File // Convert Path to File Path path = Paths.get("/home/mkyong/test/file.txt"); File file = path.toFile(); 1. Convert File to Path In Java, we can […]
In this tutorial, we will use the Apache Commons Compress library for handling TAR and GZ compression or tar.gz file. Table of Contents: 1. What is tar.gz? 2. Adding Dependencies 3. Creating a tar.gz File in Java 4. Extracting a tar.gz File in Java 5. Adding Files or Directories to an Existing tar.gz File 6. […]
This article shows how to use JSch library to run or execute a shell script in a remote server via SSH. pom.xml <dependency> <groupId>com.jcraft</groupId> <artifactId>jsch</artifactId> <version>0.1.55</version> </dependency> 1. Run Remote Shell Script This Java example uses JSch to SSH login a remote server (using password), and runs a shell script hello.sh. 1.1 Here is a […]
This article shows how to do file transfer from a remote server to the local system and vice versa, using SSH File Transfer Protocol (SFTP) in Java. P.S Tested with JSch 0.1.55 1. JSch Dependency pom.xml <dependency> <groupId>com.jcraft</groupId> <artifactId>jsch</artifactId> <version>0.1.55</version> </dependency> 2. File Transfer – JSch Examples 2.1 In JSch, we can use put and […]
This Java example tries to use Jsch to download a file from a remote server to the local system. pom.xml <dependency> <groupId>com.jcraft</groupId> <artifactId>jsch</artifactId> <version>0.1.55</version> </dependency> SFTPFileTransfer.java package com.mkyong.io.howto; import com.jcraft.jsch.*; public class SFTPFileTransfer { private static final String REMOTE_HOST = "1.1.1.1"; private static final String USERNAME = ""; private static final String PASSWORD = ""; […]
This Java example tries to use JSch to transfer a file from the local folder to a remote server using public and private keys, instead of a password. pom.xml <dependency> <groupId>com.jcraft</groupId> <artifactId>jsch</artifactId> <version>0.1.55</version> </dependency> SFTPFileTransfer.java package com.mkyong.io.howto; import com.jcraft.jsch.*; public class SFTPFileTransfer { private static final String REMOTE_HOST = "1.1.1.1"; private static final String USERNAME […]
On Linux, macOS, or Windows, we can use ssh -V (uppercase V) to check the OpenSSH version currently installed. Example 1 Terminal $ ssh -V OpenSSH_9.0p1, LibreSSL 3.3.6 Example 2 Terminal $ ssh -V OpenSSH_8.4p1 Debian-5+deb11u1, OpenSSL 1.1.1n 15 Mar 2022 References Wikipedia – OpenSSH OpenSSH Release Notes
In Java, we can use Files.size to get the size of a file; for the directory or folder size, we need to count the size of a directory recursively (sum of the Files.size of all files). This example shows a few common ways to get the size of a directory or folder. FileVisitor (Java 7) […]
In Java, we can use String.format or DecimalFormat to format a double, both support Locale based formatting. 1. String.format .2%f For String.format, we can use %f to format a double, review the following Java example to format a double. FormatDouble1.java package com.mkyong.io.utils; import java.util.Locale; public class FormatDouble1 { public static void main(String[] args) { String […]
In Java, we can use DateTimeFormatter to convert the FileTime to other custom date formats. public static String formatDateTime(FileTime fileTime) { LocalDateTime localDateTime = fileTime .toInstant() .atZone(ZoneId.systemDefault()) .toLocalDateTime(); return localDateTime.format( DateTimeFormatter.ofPattern("MM/dd/yyyy HH:mm:ss")); } 1. File Last Modified Time This example displays the last modified time of a file in a custom date format. GetLastModifiedTime.java package […]
In IntelliJ IDEA, we can press on the keyboard SHIFT key twice to open a search everywhere windows to quickly find a class or a file. Other shortcuts, seldom use, prefer double clicks on SHIFT key to open the search windows. Ctrl+N – finds a class by name. Ctrl+Shift+N – finds a file or directory […]
The newline character, also called end of line (EOL), line break, line feed, line separator or carriage return, is a control character to tell the end of a line of text, and the next character should start at a new line. On the Windows system, it is \r\n, on the Linux system, it is \n. […]
In Java, we can use the NIO createFile() to assign file permission during file creation. Files.java package java.nio.file; public static Path createFile(Path path, FileAttribute<?>… attrs) throws IOException But, the createFile() fails to assign the group writes file permission to a file on the Unix system? Path path = Paths.get("/home/mkyong/test/runme.sh"); Set<PosixFilePermission> perms = PosixFilePermissions.fromString("rwxrwxrwx"); Files.createFile(path, PosixFilePermissions.asFileAttribute(perms)); […]
For file path or directory separator, the Unix system introduced the slash character / as directory separator, and the Microsoft Windows introduced backslash character \ as the directory separator. In a nutshell, this is / on UNIX and \ on Windows. In Java, we can use the following three methods to get the platform-independent file […]
In Java, we can find the java.security file at the following location: $JAVA_HOME/jre/lib/security/java.security $JAVA_HOME/conf/security For Java 8, and early version, we can find the java.security file at $JAVA_HOME/jre/lib/security/java.security. Terminal $ /usr/lib/jvm/java-8-openjdk-amd64/jre/lib/security$ ls -lsah total 12K 4.0K drwxr-xr-x 3 root root 4.0K Mei 12 11:53 . 4.0K drwxr-xr-x 8 root root 4.0K Mei 12 11:53 .. […]
This tutorial shows how to install ModSecurity (open source web application Firewall) in Nginx, and also enable the OWASP ModSecurity Core Rule Set (CRS). Tested: Nginx Open Source 1.17.7 ModSecurity 3.0 OWASP ModSecurity CRS 3.2.2 Debian The official guide of installing ModSecurity for NGINX is very detail and well documented, and you should refer it. […]
Argon2 was the winner of the Password Hashing Competition in July 2015, a one-way hashing function that is intentionally resource (CPU, memory, etc) intensive. In Argon2, we can configure the length of the salt, the length of the generated hash, iterations, memory cost, and CPU cost to control the resources that are needed to hash […]
This article shows 3 methods or tools to make JSON output easier to read, or "pretty print" the JSON after receiving it with cURL requests. Table of contents: 1. Pretty print JSON with jq 2. Pretty print JSON with json_pp 3. Pretty print JSON with Python 4. References In the default cURL requests, the JSON […]
This article shows you five examples to convert a string into a binary string representative or vice verse. Convert String to Binary – Integer.toBinaryString Convert String to Binary – Bit Masking Convert Binary to String – Integer.parseInt Convert Unicode String to Binary. Convert Binary to Unicode String. 1. Convert String to Binary – Integer.toBinaryString The […]