Java – Convert Date to Calendar example

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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 …

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Ant and TestNG Task example

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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" …

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Maven – Get source code for Jar

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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 …

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Ant and jUnit Task example

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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" /> …

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Must include junit.jar if not in Ant’s own classpath

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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 …

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Convert DateTime to Date, but TimeZone is missing?

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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 …

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How to install Apache Ant on Windows

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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 …

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How to Apache Ant on Mac OS X

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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 …

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Windows 8.1, black screen with movable cursor

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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 …

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Ant – How to print classpath from path id

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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 …

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Java – Convert String to Enum object

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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() { …

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Linux – How to extract a tar.gz file

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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 …

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Mac OSX – What program is using port 8080

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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 …

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Mac OSX – What program is using port 80

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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 …

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Where is Eclipse deploy web application – Tomcat

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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 …

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How to debug Ant Ivy project in Eclipse IDE

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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 …

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Ant – Spring MVC and WAR file Example

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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 …

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Ant – Create a fat jar file

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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 …

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Java AWT Layouts

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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: …

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Ant – How To Create A Jar File with external libraries

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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 …

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Ant – How to create a Java Project

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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 …

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Create a fat Jar file – Maven Assembly Plugin

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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 …

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Maven – Exclude log4j.properties in Jar file

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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 …

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Java – Cron job to run a jar file

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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 …

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Create a fat Jar file – Maven Shade Plugin

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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 …

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Gradle – How to skip unit test

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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 …

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Spring MVC hello world example (Gradle and JSP)

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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 …

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How to configure hot deploy in Eclipse

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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 …

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Gradle – Create a Jar file with dependencies

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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 …

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Gradle – bootstrap class path not set in conjunction with -source 1.5

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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 …

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Gradle : Add Eclipse project nature

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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 …

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Maven – Exclude logback.xml in Jar file

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This example shows you how to use Maven to exclude the logback.xml file from the final Jar file. Note Please, DO NOT include the logback.xml into the final Jar file, it will cause multiple logback.xml files in the classpath, if someone is using your Jar, you may override other’s logging configurations accidentally. pom.xml <project> <build> …

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Nginx : Block Referrer Spam

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In this article, we will show you how to block referrer spam in one of our Nginx web server. 1. Find the Patterns Check the Nginx access.log file, and identify the “referrer spam” patterns. $ sudo tail -f /var/log/nginx/access.log Some patterns : 200 http://???.ru/engine/redirect.php?url=http://mywebsite.com/site/blogspot.com.au 200 http://???.com/tp/out.php?link=alternatevideo&url=http%3A//mywebsite.com/site/readyliftproshop.com 200 http://???.edu/online/redirect.asp?url=http://mywebsite/site/wheretoshophongkong.com We are going to block following patterns …

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Nginx + Apache Tomcat configuration example

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This tutorial shows you how to configure Nginx as a reverse proxy to redirect the traffics from port 80 to Apache Tomcat on port 8080. Here is the environment in my Linode server : Debian 7.5 Nginx 1.2.1 Tomcat 7.0.28 P.S Both Nginx and Tomcat are installed via apt-get install. 1. Tomcat Configuration Edit server.xml, …

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Java : Return a random item from a List

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Normally, we are using the following ways to generate a random number in Java. 1. ThreadLocalRandom (JDK 1.7) //Generate number between 0-9 int index = ThreadLocalRandom.current().nextInt(10); 2. Random() //Generate number between 0-9 Random random = new Random(); int index = random.nextInt(10); 3. Math.random() //Generate number between 0-9 int index = (int)(Math.random()*10); Note 1. For single …

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Nginx : Block User Agent

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In Nginx, you can block certain user agents (normally it is crawler) like this : /etc/nginx/sites-enabled/default server { listen 80; server_name mysite.com; root /etc/tomcat7/webapps/mysite; if ($http_user_agent ~* (ahrefs|wget|crawler|majestic) ) { return 403; } location / { <!– xxx –> } } In above example, for “user agent” that contains one of this pattern : ahrefs|wget|crawler|majestic, …

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Count IP address in Nginx access logs

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Recently, many referer spam hit on my server, below is the command I used to find and count the IP Address from a Nginx access log file. $ sudo awk ‘{print $1}’ /var/log/nginx/access.log | sort | uniq -c | sort -nr Full example. $ sudo awk ‘{print $1}’ /var/log/nginx/access.log | sort | uniq -c | …

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jsoup : Send search query to Google

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This example shows you how to use jsoup to send a search query to Google. Document doc = Jsoup .connect("https://www.google.com/search?q=mario"); .userAgent("Mozilla/5.0") .timeout(5000).get(); Unusual traffic from your computer network Don’t use this example to spam Google, you will get above message from Google, read this Google answer. 1. jsoup example Example to send a “mario” search …

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