Java

Put all Maven dependency versions in properties
Maven java maven
Published: 2014-05-02
Put all Maven dependency versions in properties

Because security vulnerabilities in third-party software are so common, it is important to manage the versions of your dependencies and to be prepared to upgrade them quickly. For Maven projects, I recommend putting the versions of all your dependencies in the properties section of your pom.xml. Furthermore, for libraries which require multiple dependency entries in pom.xml, this allows you to ensure you use the same version for all of those dependencies.

For example:

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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">
    <properties>
        <spring.version>3.2.6.RELEASE</spring.version>
        <jackson.version>2.2.3</jackson.version>
    </properties>
    <dependencies>
        <!-- spring -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <!-- Jackson -->
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-core</artifactId>
            <version>${jackson.version}</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
            <version>${jackson.version}</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>${jackson.version}</version>
        </dependency>
    </dependencies>
</project>
Publishing a Java Servlet to Azure Website Using Maven
Maven azure FTP java jetty maven servlet wagon-maven
Published: 2014-05-01
Publishing a Java Servlet to Azure Website Using Maven

This blog post shows how to publish a Java Servlet, encapsulated in a WAR file, to an Azure Web Site using FTP via Maven.

The first step will be to generate a simple servlet using Maven:

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mvn archetype:generate -DgroupId=com.example -DartifactId=hello-world -DarchetypeArtifactId=maven-archetype-webapp

This creates a simple, Hello World application in the hello-world directory. We can verify it works by running it in a local servlet container using the instructions found in Supporting mvn jetty:run in Maven applications. Add the Jetty maven plugin to pom.xml under the build section:

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Supporting mvn jetty:run in Maven applications
Maven java jetty maven
Published: 2014-04-30
Supporting mvn jetty:run in Maven applications

When I’m writing a Java servlet using Maven, I find it convenient to be able to run the Java servlet in a local servlet container for testing purposes. This is very easy to do using the Jetty Maven plugin.

To add the Jetty Maven plugin to your project, modify pom.xml as follows:

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<build>
    <plugins>
        <plugin>
            <groupId>org.eclipse.jetty</groupId>
            <artifactId>jetty-maven-plugin</artifactId>
            <version>9.2.0.M0</version>
        </plugin>
        ...
    </plugins>
</build>

You can then run your project in Jetty using the following command:

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Instrumenting a Java Web Application with JMX
Telemetry java jmx
Published: 2013-11-25
Instrumenting a Java Web Application with JMX

Java Management Extensions (JMX) is a technology for managing and monitoring Java applications. JMX instructs application developers how to instrument their applications to expose metrics and management mechanisms, and instructs operations teams how to collect metrics and manage Java applications. JMX is ubiquitous: there are a large number of off-the-shelf commercial and open source tools which speak JMX.

This article is intended for application developers to introduce JMX, to teach them how to create some simple metrics via JMX, and to encourage them to thoroughly instrument their applications with JMX.; This article uses only J2SE 5 and the Java Servlet specification. There may be better, more efficient, or more appropriate ways to add JMX counters to applications using other frameworks. For example, Spring developers should read http://static.springsource.org/spring/docs/2.0.x/reference/jmx.html.

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Creating a Virtual Java RPM
Java java rpm
Published: 2013-05-29
Creating a Virtual Java RPM

Some RPMs (e.g. jpackage.org’s tomcat7-7.0.39-1.jpp6.noarch.rpm) express their dependency upon Java by requiring a RPM that provides capability java (as opposed to, for example, depending on the existence of a file /usr/bin/java). On CentOS, this capability is normally provided by the java-*-openjdk RPM. Therefore, if you execute # yum install tomcat7 on a clean install of CentOS, yum will install OpenJDK in addition to Tomcat 7.

Some people prefer to run the Oracle JRE/JDK instead of OpenJDK. Oracle provides RPMs named jre-<em>version</em>-linux-x64.rpm and jdk-<em>version</em>-linux-x64.rpm to make installing them easier. Unfortunately, these RPMs do not provide the capability java. This means that if you already have the Oracle JRE installed, and you install a RPM which requires the capability java, the OpenJDK will be unnecessarily installed (and might even become the default!).

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