This Java example shows you how to display a list of TimeZone with GMT in front. P.S Tested with JDK 1.7 Java 8 You may interest at this example – Display all ZoneId and its UTC offset TimeZoneExample.java package com.mkyong.test; import java.util.TimeZone; import java.util.concurrent.TimeUnit; public class TimeZoneExample { public static void main(String[] args) { String[] […]
In this tutorial, we will show you how to enable data caching in a Spring application, and integrate with the popular Ehcache framework. Tools used Ehcache 2.9 Spring 4.1.4.RELEASE Logback 1.0.13 Maven 3 / Gradle 2 JDK 1.7 Eclipse 4.4 Note Spring supports caching since version 3.1 Spring cache has been significantly improved since version […]
Prior to MongoDB 2.6, there is no official function to $unset a field from array document. Note $unset is not working with arrays $pull is used to remove the entire record, not a particular field. 1. Arrays Documents In this article, we will show you how to remove the field “countryName” from below array. > […]
In this tutorial, we will show you two examples to help you getting started with Ehcache. Tools used : Ehcache 2.9 Maven 3 Gradle 2 JDK 1.7 P.S Ehcache required JDK 1.5 or above. 1. Project Directory Structure 2. Hello World Assume this is a Maven project : pom.xml <dependency> <groupId>net.sf.ehcache</groupId> <artifactId>ehcache</artifactId> <version>2.9.0</version> </dependency> Read […]
Review a simple Java application and log a message via Logback. App.java package com.mkyong.test; import org.slf4j.Logger; import org.slf4j.LoggerFactory; public class App { private static final Logger log = LoggerFactory.getLogger(App.class); public static void main(String[] args) { log.debug("Testing"); } } P.S Tested with Logback 1.1.2 1. Problem A simple logback.xml to log a message to console. logback.xml […]
Ehcache is using SLF4j logging, to log stuff, put a slf4j implementation in the project classpath, in this example, we use logback. Tools used : Ehcache 2.9 Maven 3 logback 1.0.13 1. Project Directory Structure 2. Project Dependencies pom.xml <dependency> <groupId>net.sf.ehcache</groupId> <artifactId>ehcache</artifactId> <version>2.9.0</version> </dependency> <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>1.0.13</version> </dependency> 3. Logback.xml Create a logback.xml file […]
Apache Ant tutorial with full example, including Ant installation, create JAR file, WAR file, working with dependency with Ivy tools , running jUnit and TestNG test and etc
In Java, you can use calendar.setTime(date) to convert a Date object to a Calendar object. Calendar calendar = Calendar.getInstance(); Date newDate = calendar.setTime(date); A Full example DateAndCalendar.java import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Calendar; import java.util.Date; public class DateAndCalendar { public static void main(String[] argv) throws ParseException { //1. Create a Date from String SimpleDateFormat sdf […]
In this tutorial, we will show you how to run a TestNG test in Ant build. 1. Run by Classes build.xml <taskdef name="testng" classname="org.testng.TestNGAntTask"> <classpath location="lib/testng-6.8.14.jar" /> </taskdef> <target name="testng" depends="compile"> <!– Assume test.path contains the project library dependencies –> <testng classpathref="test.path" outputDir="${report.dir}" haltOnFailure="true"> <!– Extra project classpath, which is not included in above "test.path" […]
In Maven, you can get source code for project dependencies in most IDEs like this : $ mvn dependency:sources $ mvn dependency:resolve -Dclassifier=javadoc Get source code for Jar Get javadoc for Jar, normally, developers don’t provide this. 1. Eclipse IDE In Eclipse IDE, it’s better to use the maven eclipse plugin: $ mvn eclipse:eclipse -DdownloadSources=true […]
In this tutorial, we will show you how to run a junit test in Ant build. 1. Run a unit test build.xml <target name="junit" depends="compile"> <junit printsummary="yes" haltonfailure="no"> <!– Project classpath, must include junit.jar –> <classpath refid="test.path" /> <!– test class –> <classpath location="${test.classes.dir}" /> <test name="com.mkyong.test.TestMessage" haltonfailure="no" todir="${report.dir}"> <formatter type="plain" /> <formatter type="xml" /> […]
Declares a junit task in Ant like this build.xml <!– Run jUnit –> <target name="junit" depends="resolve"> <junit printsummary="yes" haltonfailure="no"> <classpath refid="test.path" /> <classpath location="${build.dir}" /> <test name="com.mkyong.test.TestMessage" haltonfailure="no" todir="${report.dir}" outfile="result"> <formatter type="plain" /> <formatter type="xml" /> </test> </junit> </target> Run ant junit, but hits the following error message : BUILD FAILED build.xml:86: The <classpath> for […]
A code snippet to use Joda Time to convert a java.util.Date to different timezone : //java.util.Date : 22-1-2015 10:15:55 AM //System TimeZone : Asia/Singapore //Convert java.util.Date to America/New_York TimeZone DateTime dt = new DateTime(date); DateTimeZone dtZone = DateTimeZone.forID("America/New_York"); DateTime dtus = dt.withZone(dtZone); //21-1-2015 09:15:55 PM – Correct! //Convert Joda DateTime back to java.util.Date, and print […]
To install Apache Ant on Windows, you just need to download the Ant’s zip file, and Unzip it, and configure the ANT_HOME Windows environment variables. Tools Used : JDK 1.7 Apache Ant 1.9.4 Windows 8.1 1. JAVA_HOME Make sure JDK is installed, and JAVA_HOME is configured as Windows environment variable. 2. Download Apache Ant Visit […]
In this tutorial, we will show you how to install Apache Ant on Mac OSX. Tools : Apache Ant 1.9.4 Mac OSX Yosemite 10.10 Preinstalled Apache Ant? In older version of Mac, Apache Ant may be already installed by default, check if Apache Ant is installed : $ ant -v 1. Get Apache Ant Visit […]
Here’s the scenario, morning wake up and find out my Windows 8.1 is displaying a black screen upon boot, no login screen, but a movable white cursor, random clicks will display the small loading icons? Problem : Black screen upon boot, movable cursor. Unable to display the Windows login screen. Detail : Windows 8.1 64 […]
In Ant, you can use pathconvert task to print out the classpath from path : build.xml <path id="project.web.classpath"> <pathelement location="test/lib/junit-4.11.jar"/> <pathelement location="test/lib/hamcrest-core-1.3.jar"/> <fileset dir="${lib.web.dir}"> <include name="**/*.jar" /> </fileset> </path> <target name="print-classpath"> <pathconvert property="classpathInName" refid="project.web.classpath" /> <echo>Classpath is ${classpathInName}</echo> </target> Test : $ ant print-classpath Buildfile: /Users/mkyong/Documents/workspace/AntSpringMVC/build.xml print-classpath: [echo] Classpath is /Users/mkyong/Documents/workspace/AntSpringMVC/test/lib/junit-4.11.jar: /Users/mkyong/Documents/workspace/AntSpringMVC/testlib/hamcrest-core-1.3.jar: …… BUILD SUCCESSFUL […]
In Java, you can use Enum valueOf() to convert a String to an Enum object, review the following case study : 1. Java Enum example WhoisRIR.java package com.mkyong.whois.utils; public enum WhoisRIR { ARIN("whois.arin.net"), RIPE("whois.ripe.net"), APNIC("whois.apnic.net"), AFRINIC("whois.afrinic.net"), LACNIC("whois.lacnic.net"), JPNIC("whois.nic.ad.jp"), KRNIC("whois.nic.or.kr"), CNNIC("ipwhois.cnnic.cn"), UNKNOWN(""); private String url; WhoisRIR(String url) { this.url = url; } public String url() { […]
In this tutorial, we will show you how to extract a tar.gz file : tar vxf filename.tar.gz Example For example, apache-ant-1.9.4-bin.tar.gz in your ~/Download folder. $ cd ~ $ pwd /Users/mkyong # Optionally, create a new folder for the archived file. $ mkdir tools $ cd tools $ pwd /Users/mkyong/tools # Copy archived file to […]
By default, most Java web application servers are listening on port 8080, and it can easily cause the popular 8080 port conflict error. In Mac OSX, you can use sudo lsof -i :8080 | grep LISTEN to find out what program is listening on port 8080 : In terminal $ lsof -i :8080 | grep […]
In Mac OSX, you can use sudo lsof -i :80 to find out what program is using or listening on port 80 : In terminal $ sudo lsof -i :80 Password: COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME httpd 12649 root 5u IPv6 0xede4ca21f607010b 0t0 TCP *:http (LISTEN) httpd 12650 _www 5u IPv6 […]
By default Eclipse deploys web application to a internal plugin folder called wtpwebapps, which is located in the following directory : {Your_Workspace}/.metadata/.plugins/org.eclipse.wst.server.core/tmp{number}/wtpwebapps #Example 1 – Windows C:\Users\mkyong\workspace\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps #Example 2 – Mac OSX /Users/mkyong/Documents/workspace/.metadata/.plugins/org.eclipse.wst.server.core/tmp0/wtpwebapps How it works In Server view, double clicks on the “Tomcat Server”, the deployment work is defined in the Server Locations To […]
In this tutorial, we will show you how to debug an Ant-Ivy web project in Eclipse IDE. Technologies used : Eclipse 4.2 Eclipse Tomcat Plugin Ant 1.9.4 Apache IvyDE Spring 4.1.3.RELEASE Note Previous Ant Spring MVC web project will be reused. 1. Install Apache IvyDE Install Apache IvyDE, it integrates Ivy into Eclipse IDE. Restart […]
In this tutorial, we will show you how to use Ant build script to manage a Spring MVC web application project, create a WAR file and deploy to Tomcat. Technologies used : Eclipse 4.2 JDK 1.7 Ant 1.9.4 Ant-Ivy 2.4 logback 1.1.2 jstl 1.2 Spring 4.1.3.RELEASE Tomcat 7 1. Project Directory Review the final project […]
In this tutorial, we will show you how to use Ant build script to create a big far / uber Jar file, which mean include the entire project external dependencies into a single jar file. Technologies used : Ant 1.9.4 Ant-Ivy 2.4 logback 1.1.2 joda-time 2.5 1. Create a Fat Jar Previous Ant + External […]
The java.awt library provides 5 basic layouts. Each layout has its own significance and all of them are completely different. Here in this article, we will discuss how to apply any layout to a frame or a panel and also discuss about each layout in brief. The 5 layouts available in the java.awt library are: […]
In this tutorial, we will show you how to use Ant build script to create a Jar file and working with the project’s external libraries / dependencies. Technologies used : Eclipse 4.2 JDK 1.7 Ant 1.9.4 Ant-Ivy 2.4 logback 1.1.2 joda-time 2.5 P.S Previous Ant Java project will be reused. 1. Project Structure Figure 1.1 […]
In this tutorial, we will show you how to use Ant build tool to manage a Java project, compile, and package it into a Jar file. Technologies used : Eclipse 4.2 Ant 1.9.4 JDK 1.7 1. Create a Java Project In Eclipse IDE, create a new Java project named “AntDateUtils”. 2. Java Source Code Create […]
In this tutorial, we will show you how to create a fat/uber jar with Maven Assembly Plugin. Which means create a Jar together with its dependency Jars into a single executable Jar file. Note Maven assembly plugin is not good in producing fat/uber jar, it may cause name conflict issue, it is better to use […]
This example shows you how to use Maven to exclude the log4j.properties file from your Jar file. Note Please, DO NOT include the log4j.properties into the final Jar file, it will cause multiple log4j.properties files in the classpath, if someone is depending on your Jar, you may accidentally override their logging configurations, depends which Jar […]
In this tutorial, we will show you how to use Maven build tool, One-JAR plugin to create a single Jar together with its dependency Jars into a single executable Jar file, so called fat Jar. Tools used : Maven 3.1.1 JDK 1.7 Joda-time 2.5 1. Create a simple Java project Create a Java project from […]
Quartz is good, but often times we just need a simple scheduler system to run a jar file periodically. On *unix system, you can use the build-in cron to schedule a scheduler job easily. In this example, we will show you how to create a cron job on *nix to run a jar file, by […]
This article covers 3 ways to read a text file line by line : Java NIO libraries – FileChannel to read the files. It is a non-blocking mode of reading files BufferedReader – Which is a blocking operation i.e it blocks any other read/write request to the file until it has completed the task. Apache […]
In this tutorial, we will show you how to use Maven Shade Plugin to create a Jar together with its dependency Jars into a single executable Jar file, so called fat Jar or uber Jar. Note Maven Shade plugin is a better plugin to create fat/uber jar, if compare with assembly plugin, because it provides […]
Be default, Gradle build is abort if any unit tests is failed. Oftentimes, we still need to build the project even the unit test is failed. To skip the entire unit tests in Gradle build, uses this option-x test gradle build -x test Review a sample output : 1. Default Gradle build : $ gradle […]
This tutorial shows you how to create a Spring Web MVC application with the Jakarta Server Pages (JSP; formerly JavaServer Pages) template. Technologies and tools used: Java 11 Spring 5.2.22.RELEASE JSP JSTL 1.2 Servlet API 4.0.1 Bootstrap 5.2.0 (webjars) IntelliJ IDEA Gradle 7.5.1 Gradle Gretty plugin 3.0.9 for embedded servlet containers (Tomcat 9 and Jetty […]
In this tutorial, we will show you how to configure Eclipse debugger to support hot deploy, hot swap or hot code replace without restarting the Server, this speed development a lot. Environment : Eclipse 4.4 (Supported in older version as well) Eclipse Tomcat Plugin 1. Hot deploy example Review a simple hot deploy example, code […]
In this tutorial, we will show you how to use Gradle build tool to create a single Jar file with dependencies. Tools used : Gradle 2.0 JDK 1.7 Logback 1.1.2 1. Project Directory Create following project folder structure : By default, Gradle is using the standard Maven project structure. ${Project}/src/main/java/ ${Project}/src/main/resources/ ${Project}/src/test/java/ 2. Java Files […]
My environment : JDK 1.7 Eclipse 4.4 Gradle 2.0 While gradle builld the project, I get following compile warning message : :compileJavawarning: [options] bootstrap class path not set in conjunction with -source 1.5 1 warning Figure : Eclipse console view. Solution The warning is saying you are using JDK 1.7, but try to compile the […]
Eclipse project natures are configured in the .project file. For example : .project <?xml version="1.0" encoding="UTF-8"?> <projectDescription> <name>hello</name> <comment></comment> <projects> </projects> <buildSpec> <buildCommand> <name>org.eclipse.jdt.core.javabuilder</name> <arguments> </arguments> </buildCommand> </buildSpec> <natures> <nature>org.springsource.ide.eclipse.gradle.core.nature</nature> <nature>org.eclipse.jdt.core.javanature</nature> </natures> </projectDescription> To add a nature, just modify the nature tag, and add whatever nature you want. In Gradle, you can add the Eclipse […]
