The idleMonitor component, monitor user action and fire when user goes idle or active again. By default, the idle time is set to 5 minutes (300000 ms), and you can customize the duration via timeout attribute like below : <!– fire if user idle for 10 seconds –> <p:idleMonitor timeout="10000" onidle="idleDialog.show()" /> In this tutorial, […]
By default, all logging messages will output to log console. To change the logging settings, find this file – {Google App Engine SDK directory}\google\appengine\tools\dev_appserver_main.py. File : dev_appserver_main.py – Find following pattern #… import getopt import logging import os import signal import sys import tempfile import traceback logging.basicConfig( level=logging.INFO, format=’%(levelname)-8s %(asctime)s %(filename)s:%(lineno)s] %(message)s’) #… Output to […]
In this tutorial, we will show you how to create a simple GAE hello world web project, using Python, on Mac OS X, and run it via Google App Engine Launcher. Tools used : Google App Engine SDK for Python (Mac OS X) – 1.7.0 Mac OS X 10.8 Python 2.7 Note By default, Mac […]
In this tutorial, we show you two ways to find large files on Mac OS X. Built-in search tools Find command 1. Search Tools To open the search tools, do following : Mac OS X Desktop, run Finder. Press Command+F to open “Search Tools” (it also can be located from menu -> File -> Find). […]
In this tutorial, we will show you how to create a JSF 2 + PrimeFaces wed project, the final output is display a “hello world” string in PrimeFaces editor component. Tools used : JSF 2.1.11 Primefaces 3.3 Eclipse 4.2 Maven 3 Tested on Tomcat 7 Note PrimeFaces only requires a JAVA 5+ runtime and a […]
I was recently in a situation of having to change some text that appeared in a bunch of config files that were inside nested sub-directories. Not having time to dust off 10-year old perl skills, I was looking for some shell commands that would work. Surprisingly, there are many examples on the web that do […]
See following scenario, create a file, add content, search and replace it. $ touch testing.txt $ echo "this is mkyong.com" > testing.txt $ cat testing.txt this is mkyong.com $ sed -i ‘s/mkyong/google/g’ testing.txt sed: 1: "testing.txt": undefined label ‘esting.txt’ This sed -i ‘s/mkyong/google/g’ testing.txt command is working properly in Linux, but hits “undefined label” error […]
Below are two code snippets to show you how to list all Quartz jobs. Quartz 2 APIs are changed a lot, so syntax is different from Quartz 1.x. 1. Quartz 2.1.5 example Scheduler scheduler = new StdSchedulerFactory().getScheduler(); for (String groupName : scheduler.getJobGroupNames()) { for (JobKey jobKey : scheduler.getJobKeys(GroupMatcher.jobGroupEquals(groupName))) { String jobName = jobKey.getName(); String jobGroup […]
The ServletContext class is important in web application, often times, you need this class get the information of current deployed servlet container. Here’s a trick to show you how to get ServletContext in JSF2, via FacesContext. ServletContext servletContext = (ServletContext) FacesContext .getCurrentInstance().getExternalContext().getContext(); References ServletContext JavaDoc FacesContext JavaDoc
In Quartz, you can trigger a job manually via following pattern : JobKey jobKey = new JobKey(jobName, jobGroup); scheduler.triggerJob(jobKey); //trigger a job by jobkey In this tutorial, we will show you a JSF 2 web application, display all the Quartz jobs on dataTable, and allow user to click a link o fire the job manually. […]
In *nix, you can use the find command to find a file easily. $find {directory-name} -name {filename} 1. Find a file in the root directory If you have no idea where the file is located, you can search the entire system via the “/” root directory. Below example shows you how to find a file, […]
In this example, we show you how to declare multiple Quartz jobs via Quartz APIs, Quartz XML and Spring. In Quartz scheduler framework, each job will be attached to an unique trigger, and run it by scheduler. P.S In Quartz, one trigger for multiple jobs is not possible. (Correct me if this is wrong.) 1. […]
Quartz, is a open source job scheduling framework, that let you scheduler a task to run on a predefine date and time. Happy learning Quartz 🙂 1. Quick Start Hello world to Quartz scheduler frameworks. Quartz 1.6 hello world example The old and popular Quartz 1.6.3, legacy system may still using this. Quartz 2 hello […]
In this tutorial, we show you how to run a Quartz job during JSF web application via QuartzInitializerListener listener class in Quartz library. This solution is not only works with JSF 2, the concept is applicable on almost all standard Java web application. Tools Used : JSF 2.1.11 Quartz 2.1.5 Maven 3 Eclipse 4.2 Tomcat […]
You can use latest Java 6’s Collection API to navigate a set and Map collections. These API gives a lot of flexibility to find out required result from the collection. 1. NavigableMap Example package com.example.collection; import java.util.NavigableMap; import java.util.TreeMap; public class NavigableMapDemo { public static void main(String[] args) { NavigableMap<String,Integer> navigableMap=new TreeMap<String, Integer>(); navigableMap.put("X", 500); […]
Developing Quartz 2.1.5 + Spring 3.1.2.RELEASE, hits following error messages : Caused by: java.lang.IncompatibleClassChangeError: class org.springframework.scheduling.quartz.JobDetailBean has interface org.quartz.JobDetail as super class at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(ClassLoader.java:631) at java.lang.ClassLoader.defineClass(ClassLoader.java:615) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141) at org.apache.catalina.loader.WebappClassLoader.findClassInternal(WebappClassLoader.java:2901) at org.apache.catalina.loader.WebappClassLoader.findClass(WebappClassLoader.java:1170) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1678) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1556) at org.springframework.util.ClassUtils.forName(ClassUtils.java:258) … 19 more Solution Quartz 2 APIs are changed a lot, and someone already […]
Developing Quartz with Spring 3, and hits following error message. Caused by: java.lang.NoClassDefFoundError: org/springframework/transaction/TransactionException at java.lang.Class.getDeclaredConstructors0(Native Method) at java.lang.Class.privateGetDeclaredConstructors(Class.java:2389) at java.lang.Class.getConstructor0(Class.java:2699) at java.lang.Class.getDeclaredConstructor(Class.java:1985) ….. Caused by: java.lang.ClassNotFoundException: org.springframework.transaction.TransactionException at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1711) at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1556) … 29 more Solution Doesn’t matter with Quartz, above error message show that you need Spring transaction dependency. To fix it, just include […]
Sometimes we need copy properties from a Java class to other, we can do it this manually or with our own reflection implementation, but in this case use us reflection for automate it with a utility from apache Requirements commons-beanutils , you can download from here http://commons.apache.org/beanutils/ commons-loging , you can download from here http://commons.apache.org/logging/ […]
Twitter, provides many APIs to deal with Tweets. In this example we are going to learn how to use jQuery to get last tweet of a user. Twitter API Get the last tweet of user (change “username” in the url with Twitter username you want) http://search.twitter.com/search.json?q=from:username&rpp=1 For example, get last tweet from twitter’s user “mkyong”. […]
Some java application need to execute a method between a regular interval of time. For example GUI application should update some information from database. 1. Scheduler Task For this functionality, You should create a class extending TimerTask(available in java.util package). TimerTask is a abstract class. Write your code in public void run() method that you […]
The requirement : We need to show a collapsable content when we clicked ‘Show’ button, and hide the collapsable content when we clicked ‘Hide’ button. The solution : Create a custom jQuery plugin. Demo : Clicks on the “show” button. Note Here’s the alternative solution – jQuery toggle() function. 1. Collapsable content Below is an […]
Problem Import a Java web project in Eclipse, build with Maven, once create a Tomcat server instance, unable to add the Java web project, and showing Tomcat version 6.0 only supports J2EE 1.2, 1.3, 1.4, and Java EE 5 Web modules Tools used : Eclipse Juno 4.2 Tomcat 6.0.35 JDK 1.6 Solution In project, “.settings” […]
The requirement : We need to show a collapsable content when we clicked ‘Show’ button, and hide the collapsable content when we clicked ‘Hide’ button. The solution : jQuery toggle() function. Demo : Clicks on the “show” button. 1. Collapsable Content Below is an example of HTML for collapsable content: <section class="round-border"> <h2>Use jQuery toggle […]
A simple jQuery example to show you how to implement a watermark text effect on an input field. 1. Code Snippets An email input field and css watermark class. <style type="text/css"> input.watermark { color: #999; } //light silver color </style> <label>Email : </lable> <input id="email" type="text" /> jQuery to apply the watermark effect on email […]
In this tutorial, we will show you how to create a JobListener, to keep track the running jobs status, like when the job is finished. P.S This example is tested with Quartz 2.1.5 1. Quartz Job Job, print a simple message, and throw a JobExecutionException for testing. File : HelloJob.java package com.mkyong.quartz; import org.quartz.Job; import […]
Demo : Try clicks on the tab When I developing my foodshaker.com. There is requirement for me to create a multi tab navigation to hide and show tab content. In order to develop a lightweight multitab, I decided to use jQuery and CSS to facilitate it. 1. Explanation Below is an example of navigation: <div> […]
Quartz, enterprise scheduler job framework, to help Java application to scheduler a job/task to run at a specified date and time. This tutorial show you how to develop a scheduler job using latest Quartz library 2.1.5. Note Quartz 2 involves significant API changed, read this for older Quartz 1.6.3 example. 1. Download Quartz You can […]
By default, Maven 3 is installed on Mac OSX.
Recently, answered an question about leading zero problem ZipCode, what is the most proper data type for country’s zip code? 1. ZipCode – int In Java, some claimed it should declare as “int”, and use DecimalFormat to format and display the leading zero. For example, package com.mkyong; import java.text.DecimalFormat; public class ZipCodeExample { public static […]
Working with Quartz 2, when running the project, hits following error message? org.quartz.SchedulerConfigException: Thread count must be > 0 at org.quartz.simpl.SimpleThreadPool.initialize(SimpleThreadPool.java:245) at org.quartz.impl.StdSchedulerFactory.instantiate(StdSchedulerFactory.java:1255) at org.quartz.impl.StdSchedulerFactory.getScheduler(StdSchedulerFactory.java:1484) at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4791) at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5285) at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1559) at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1549) at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) at java.util.concurrent.FutureTask.run(FutureTask.java:138) at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) at java.lang.Thread.run(Thread.java:680) Solution You have defined a “quartz.properties” file, and override the […]
In this Java example, we show you how to get content of a page from URL “mkyong.com” and save it into local file drive, named “test.html”. package com.mkyong; import java.io.BufferedReader; import java.io.BufferedWriter; import java.io.File; import java.io.FileWriter; import java.io.IOException; import java.io.InputStreamReader; import java.net.MalformedURLException; import java.net.URL; import java.net.URLConnection; public class GetURLContent { public static void main(String[] args) […]
Google App Engine, a cloud computing platform for hosting web application in existing Google infrastructure, it’s easy to scale, manage and free to use up to a predefined consumed resources, and it supports Java. For additional charged, please refer to this GAE billing . In this series of tutorials, we will show you a list […]
Note This tutorial is more on practice guide, please refer to this official Using JDO in datastore for detail explanation. See following code snippets to perform CRUD on GAE datastore, using Java Data Objects(JDO). Just annotate the Customer with JDO annotation and perform the CRUD via PersistenceManager. Add Customer c = new Customer(); c.setName(name); PersistenceManager […]
GAE datastore Refer to this official “Using datstore guide” to understand what is GAE datastore. See following code snippets to perform CRUD for Google App Engine datastore, Java, using low-level API. Add Store a customer into datastore, with “name” as the key. Key customerKey = KeyFactory.createKey("Customer", "your name"); Entity customer = new Entity("Customer", customerKey); customer.setProperty("name", […]
In this tutorial, we will show you how to create a scheduler task or cron job on Google App Engine, for Java. In GAE, cron job uses HTTP GET request to call an URL, the duration of the cron job running time is limited to run up to 10 minutes only, if excess, GAE kill […]
In GAE, Java App, you can use command “appcfg request_logs” to download or export the logs from GAE to your computer, see signature below : AppCfg [options] request_logs <app-dir> <output-file> You can type “appcfg request_logs” to view all available options. 1. What is <app-dir> ? This is NOT your app_id nor any deployed web path […]
Google App Engine for Java is using java.util.logging.Logger to perform the logging. In this tutorial, we show you how to do logging in GAE environment. 1. Logging Example Example to define a logger in MovieController, and log the messages in different logging levels (info, warning and error) import java.util.logging.Logger; //… @Controller @RequestMapping("/movie") public class MovieController […]
The “maxlength” attribute is not supported in textArea, but you can use JavaScript to limit the length of textArea dynamically. HTML 5 The textArea “maxlength” attribute is supported in HTML 5, the problem is not all browsers support HTML 5, especially, the old IE. jQuery Example A jQuery example to implement the “maxlength” effect on […]
In this tutorial, we will show you how to develop and deploy a Spring 3.0 MVC REST web application in Google App Engine (GAE) environment. Tools and technologies used : Google App Engine Java SDK 1.6.3.1 Spring 3.1.1 JDK 1.6 Eclipse 3.7 + Google Plugin for Eclipse Note This example is going to reuse this […]
This article shows how to convert an PNG image format to an JPEG image format in Java. 1. PNG Image Below is a PNG image with a transparent background. 2. Java Convert PNG to JPEG Since the JPEG image format doesn’t support the transparent background, we will create a white background as a replacement. Below […]
