This extends the 01: Docker Tutorial – compile & run Helloworld.java. Keep the container running Docker containers are designed to shut down immediately after initial CMD or ENTRYPOINT command is run. To make it keep running you can change the last line to
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CMD /app/run.sh && tail -f /dev/null |
Delete all stopped containers
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~/projects/docker-hadoop]$ docker rm $(docker ps -a -q) |
-a...
Drools allow you to externalize business rules to a database, excel spreadsheet, etc. In this tutorial let’s look at an OrderItem scenario where each OrderItem needs to be put through a couple of rules to determine its discounted price. Step 0: Dependency jars an structure Step 1: OrderItem.java. … Read...
This extends 01: Getting started with Jenkins on Docker tutorial. In this tutorial we will be using Jenkins to “checkout” an existing Scala project from “GitHub” repository, and then build the project using Maven. … Read more ›...
This is an extension to the JasperReport step by step tutorial (Part-1) to demonstrate how to generate a Excel file from the Main.java. To generate an Excel file, you need Apache POI as a dependency. Here are the Maven dependency files required.
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<!-- Jasper reports --> <dependency> <groupId>net.sf.jasperreports</groupId> <artifactId>jasperreports</artifactId> <version>5.0.1</version> </dependency> <dependency> <groupId>org.codehaus.groovy</groupId> <artifactId>groovy-all</artifactId> <version>2.1.1</version> </dependency> <dependency> <groupId>com.lowagie</groupId> <artifactId>itext</artifactId> <version>2.1.7</version> </dependency> <dependency> <groupId>org.apache.poi</groupId> <artifactId>poi</artifactId> <version>3.7</version> <optional>true</optional> </dependency> |
Now, … Read more ›...
A stream is an infinite sequence of consumable elements (i.e a data structure) for the consumption of an operation or iteration. Any Collection<T> can be exposed as a stream. It looks complex, but once you get it, it is very simple. The operations you perform on a stream can either...
Prerequisite
Uses Java 17 with Maven 3, and ensure they are installed and in the path. For example in mac, the ~/.bash_profile should have:
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... export JAVA_HOME="$(/usr/libexec/java_home -v 17)" export M3_HOME=/Users/ak/tools/apache-maven-3.9.4 ... export PATH=$SPARK_HOME/bin:$JAVA_HOME/bin:$M3_HOME/bin:${PATH} ..... |
and source it.
1. Create an empty Maven project
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C:\Temp\Java\projects>mvn archetype:generate -DgroupId=com.mytutorial -DartifactId=simple-grpc-2 |
and import or open into an IDE of your choice.
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This tutorial extends JAXB Tutorial for XML processing in Java step by step – unmarshall & marshall
When to use JAXB with StAX?
When you want to process large XML files, reading the whole file into memory can cause “OutOfMemoryError” as discussed in Java String &
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Step 1: pom.xml file with commons-dbcp2 for the connection pooling and abstraction layer for the datasource.
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<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.mytutorial</groupId> <artifactId>simple-persistence</artifactId> <packaging>jar</packaging> <version>1.0-SNAPSHOT</version> <name>simple-persistence</name> <url>http://maven.apache.org</url> <properties> <maven.compiler.source>1.8</maven.compiler.source> <maven.compiler.target>1.8</maven.compiler.target> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.12</version> <scope>test</scope> </dependency> <!-- MySQL Driver --> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>6.0.6</version> </dependency> <!-- Connection Pool --> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-dbcp2</artifactId> <version>2.1.1</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-shade-plugin</artifactId> <executions> <execution> <phase>package</phase> <goals> <goal>shade</goal> </goals> </execution> </executions> </plugin> </plugins> </build> </project> |
db.properties for connection details
Step 2: Create a new source folder “src/main/resources”.
Step 3: Define the MySQL database “learnjavadb” connection properties in a new file named “db.properties”
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This extends Install Kubernetes (i.e. minikube) on Mac. Project Structure Step 1: Create a new “project” folder “minikube-js” under the projects folder. In that folder create minikube-js/server.js file.
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var http = require('http'); var handleRequest = function(request, response) { console.log('Received request for URL: ' + request.url); response.writeHead(200); response.end('Hello World!'); }; var www = http.createServer(handleRequest); www.listen(8080); |
Step 2: Create the “ … Read more ›...
This extends the Redis tutorial Redis server & cli on Docker tutorial step by step.
1. Redis Docker compose file without password auth
Here is the docker-compose.yml file created under ~/projects folder. The server starts without a password for demonstration purpose only.
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This tutorial extends the previous tutorial Simple Akka tutorial in Java step by step to use multiple actors. Let’s have two different actors to handle odd and even numbers respectively. We will also print the thread names. Step 1: Actor “ConsumerOfOddNumbers.java” that runs on the “ … Read more ›...
This tutorial extends the previous tutorial Simple Akka Tutorial in Scala step by step for the Java developers, and Simple Akka tutorial in Java with 2 Actors.
Step 1: The “Consumer.scala” file that contains two actor classes “ConsumerOfOddNumbers”
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This tutorial extends Simple Spring Boot Tutorial in 8 steps. Step 1: The pom.xml file that was created in the previous Spring boot tutorial needs to be changed from “spring-boot-starter-actuator” to “spring-boot-starter-web”
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<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.mytutorial</groupId> <artifactId>simple-spring-boot</artifactId> <packaging>jar</packaging> <version>1.0-SNAPSHOT</version> <name>simple-spring-boot</name> <url>http://maven.apache.org</url> <parent> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-parent</artifactId> <version>1.5.4.RELEASE</version> </parent> <properties> <maven.compiler.source>1.8</maven.compiler.source> <maven.compiler.target>1.8</maven.compiler.target> <java.version>1.8</java.version> </properties> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> </dependencies> <build> <plugins> <plugin> <!-- Build an executable JAR --> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-jar-plugin</artifactId> <configuration> <archive> <manifest> <addClasspath>true</addClasspath> <classpathPrefix>lib/</classpathPrefix> <mainClass>com.mytutorial.App</mainClass> </manifest> </archive> </configuration> </plugin> <plugin> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-maven-plugin</artifactId> </plugin> </plugins> </build> </project> |
Step 2: Add additional logic to the “ … Read more ›...