jsoup : Send search query to Google
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… Continue Reading
jsoup
Java – Read a file from resources folder
In this tutorial, we will show you how to read a file from a resources folder, in both Java and Unit Test environment. In simple, put files in a resources folder, and read the file with following code snippets : ClassLoader classLoader = getClass().getClassLoader(); File file = new File(classLoader.getResource("file/test.xml").getFile()); 1.… Continue Reading
java
How to change Tomcat manager default path ?
By default, Tomcat’s manager webapp is able to access via yourapp:8080/manager. It is a good practice to change the default /manager to something else, to avoid potential brute force attack. Environment Tomcat 7 (apt-get install) Debian 7.5 1. Solution This article show you how to change / rename the default… Continue Reading
secure tomcat tomcat tomcat manager How to change Tomcat to use JDK 7
The current environment is using Tomcat 7 + JDK 1.6. Installed a JDK 1.7, but how to tell Tomcat to use the latest JDK? Environment Tomcat 7 (apt-get install) Debian 7.5 JDK 6 and JDK 7 1. Solution By default, Tomcat will pick up the JDK which configured in the… Continue Reading
tomcat Find out Tomcat is using which JDK or JAVA_HOME
In this article, we will show you how to find out which JRE / JDK or JAVA_HOME is used by the Tomcat container. Environment : Debian 7.5 Tomcat 7, installed via apt-get JDK 6 and JDK 7 Note To understand how Tomcat pick up which JDK to run, refer to… Continue Reading
tomcat
Eclipse – red-x icon didn’t display on project explorer
In Eclipse IDE, If a project contains errors, a small “red-x” icon will be displayed in the files that are causing the error. This useful feature is supported in Java related perspectives only, for example, “Package Explorer”. 1. Problem Personally, I prefer to use the “Project Explorer” perspective (pure folder… Continue Reading
eclipse
MongoDB : write Aggregation result into a new collection
This article shows you 2 ways to export a MongoDB “aggregation” result into another new collection. 1. $out Example This $out operator is New in version 2.6. 1.1 Review a simple grouping example, it writes the result to a new variable “result”. > var result = db.hc_hosting.aggregate( { $group :… Continue Reading
aggregation mongodb
Ubuntu : Status 14: The disk contains an unclean file system
Dual boot Windows and Ubuntu, but Ubuntu is unable to access the Windows partition /dev/sdb3, shows the following error message : Error mounting /dev/sdb3 … status 14: The disk contains an unclean file system (0, 0). Metadata kept in Windows cache, refused to mount. Failed to mount ‘/dev/sdb3′: Operation not… Continue Reading
ubuntu
Linux : How to gzip a folder
On Linux, gzip is unable to compress a folder, it used to compress a single file only. To compress a folder, you should use tar + gzip, which is tar -z. Note $ tar –help -z, -j, -J, –lzma Compress archive with gzip/bzip2/xz/lzma For example, tar -zcvf outputFileName folderToCompress 1.… Continue Reading
gzip mongoimport unable to import $numberLong
A collection with NumberLong type data as follows : > db.hc_whois.findOne(); { "_id" : NumberLong(3000001), "startIpInLong" : NumberLong(1543503872), "endIpInLong" : NumberLong(1544552447), "name" : "ap-net-1", //… } Export it with mongoexport : server1 $ mongoexport -d mydb -c hc_whois -o whois.json whois.json { "_id" : { "$numberLong" : "3000001" }, "startIpInLong"… Continue Reading
mongoimport Java : Unsupported major.minor version 51.0
1. Problem Run a “jar” on Debian 7.5, and hits the following error messages : $ java -jar ripecrawler.jar Exception in thread "main" java.lang.UnsupportedClassVersionError: com/mkyong/whois/job/RipeCrawlJob : Unsupported major.minor version 51.0 at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:643) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader.defineClass(URLClassLoader.java:277) at java.net.URLClassLoader.access$000(URLClassLoader.java:73) at java.net.URLClassLoader$1.run(URLClassLoader.java:212) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:205) at… Continue Reading
java error servlet-api-2.5.jar – jar not loaded
Deployed a “war” file on Tomcat, and hits following error messages : Jul 17, 2014 7:59:55 PM org.apache.catalina.loader.WebappClassLoader validateJarFile INFO: validateJarFile(D:\apache-tomcat-7.0.53\webapps\hc\WEB-INF\lib\servlet-api-2.5.jar) – jar not loaded. See Servlet Spec 3.0, section 10.7.2. Offending class: javax/servlet/Servlet.class Tools used : JDK1.7 Maven 3 Tomcat 7 1. Reason The Tomcat’s container comes with own… Continue Reading
java error
JSF 2 + Log4j Integration Example
In this tutorial, we will show you how to integrate the log4j framework with the JSF 2.x web application. JSF is using java.util.logging, you need extra works to redirect the logging from JSF’s java.util.logging to log4j, with a serious penalty of performance, make sure use this trick only during local… Continue Reading
jsf2 log4j
Log4j hello world example
In this tutorial, we will show you how to use the classic log4j 1.2.x to log a debug or error message in a Java application. 1. Project Directory Review the final project structure, a standard Maven style Java project. 2. Get Log4j Declares the following dependencies : pom.xml <dependency> <groupId>log4j</groupId>… Continue Reading
hello world log4j
Download file from server using SSH
Normally, you use Secure copy or SCP to download a file from another server via SSH connection. For example, scp username@remotehost:remoteFileToDownload localFolderNameToSaveTheFile 1. SCP Examples 1.1 Download File From Server Example to download a log file (hc.audit.log) from server (198.58.x.x), into your current local folder. scp [email protected]:/var/log/tomcat7/hc.audit.log . 1.2 Upload… Continue Reading
scp ssh
