mkyong

unix / linux July 22, 2009 1 min read by mkyong 1 comment

How to download a website in Linux (wget)

The wget is a useful command to download a website in Linux. For example , wget [url]. [mkyong@snake ~]$ wget -r -p -k -E http://www.google.com –2009-07-19 14:07:27– http://www.google.com/ Resolving www.google.com… 64.233.189.104 Connecting to www.google.com|64.233.189.104|:80… connected. HTTP request sent, awaiting response… 302 Found Location: http://www.google.com.my/ [following] –2009-07-19 14:07:27– http://www.google.com.my/ Resolving www.google.com.my… 64.233.189.147 Connecting to www.google.com.my|64.233.189.147|:80… connected. […]

web development July 22, 2009 2 min read by mkyong 3 comments

svn+ssh hit Connection closed unexpectedly error in Eclipse – (Solution)

Latest Eclipse IDE is required to support the hibernate tools plug-in. However my “svn+ssh” is not working correctly after updated to the latest Eclipse IDE and Subeclipse version of 1.6.x. While i initial the “svn+ssh” access connection in Eclipse IDE, i had encountered the following error message. Network connection closed unexpectedly svn: Connection closed unexpectedly […]

game July 21, 2009 1 min read by mkyong 16 comments

How to fix Left 4 dead always crashes issue?

While i playing the left 4 dead game after 5 to 20 minutes, it always crashes and return back to Windows. I try to find Left 4 Dead patch file to fix it, but failed, Left 4 dead does not release any patch file for it. To fix Left 4 Dead crashes issue, we need […]

unix / linux July 20, 2009 1 min read by mkyong 3 comments

How to check reboots history in Linux

As Unix / Linux server administrator, we always need to know when is our last rebooted date and time. Actually, we are able to list out the system rebooted history by issue following command. last reboot Output mkyong@mkyong:~$ last reboot reboot system boot 2.6.28-11-generi Thu Jul 16 21:42 – 23:46 (02:04) reboot system boot 2.6.28-11-generi […]

unix / linux July 18, 2009 1 min read by mkyong 2 comments

How to display the real-time memory usage in Linux

Often times, we need to monitor our Linux server memory usage, “watch” is a handy command to display the real-time memory usage in Linux. NAME watch – execute a program periodically, showing output fullscreen We can issue the following command to keep track the real time memory usage in Linux. watch -d free -m The […]

unix / linux July 17, 2009 1 min read by mkyong 0 comments

How to Limit the application CPU usage in Linux (CPUlimit)

CPULimit is a simple program to limit the CPU usage of certain application in Linux. It’s reside in the Ubuntu repositories by default. We can install it by issue the following command in Ubuntu sudo apt-get install cpulimit Output mkyong@mkyong:~$ sudo apt-get install cpulimit [sudo] password for mkyong: Reading package lists… Done Building dependency tree […]

unix / linux July 16, 2009 1 min read by mkyong 3 comments

How to find files older than certain year or minute in Linux

In some cases, we want to find files that older than certain year , let say 1 year, we can use the -mtime +1 argument. In other hand, if we want to find files that older than certain minute, let say 1 minute, we can use -mmin +1 argument. man find find the following statement […]

unix / linux July 16, 2009 2 min read by mkyong 1 comment

How to know the Hardware Details in Linux

The “dmidecode” is a handy tool in Linux to display the hardware specification detail. For example, memory, processor , BIOS and etc. man dmidecode DMI TYPES The SMBIOS specification defines the following DMI types: Type Information —————————————- 0 BIOS 1 System 2 Base Board 3 Chassis 4 Processor 5 Memory Controller 6 Memory Module 7 […]

java July 14, 2009 1 min read by mkyong 12 comments

How to get the Tomcat home directory in Java

Q : Is there a function in Java to retrieve the Tomcat (Catalina) home directory? A : Yes, Tomcat home directory or Catalina directory is stored at the Java System Property environment. If the Java web application is deployed into Tomcat web server, we can get the Tomcat directory with the following command System.getProperty("catalina.base");

java July 11, 2009 1 min read by mkyong 5 comments

Java – How to convert Char to String

A Java example to show you how to convert a Char into a String and vise verse. ConvertCharToString.java package com.mkyong.utils; public class ConvertCharToString { public static void main(String[] args) { String website = "https://mkyong.com"; //convert a String into char char charH = website.charAt(0); //h char charP = website.charAt(3);//p char charM = website.charAt(11);//m System.out.println(charH); System.out.println(charP); System.out.println(charM); […]

javascript July 6, 2009 1 min read by mkyong 4 comments

How to preload an image in JavaScript or HTML code?

Often times, we need to “preload” an image into browser’s cache for performance concern. For instance, we have a mouseover event and the image needs to be update without any delay. This “Preloading” stuff can be achieved in two ways , either JavaScript or HTML code. Javascript We can “preload” an image with the following […]

unit test May 23, 2009 9 min read by mkyong 55 comments

JUnit 4 Vs TestNG – Comparison

JUnit 4 and TestNG are both very popular unit test framework in Java. Both frameworks look very similar in functionality. Which one is better? Which unit test framework should I use in Java project? Here I did a feature comparison between JUnit 4 and TestNG. 1. Annotation Support The annotation supports are implemented in both […]

unit test May 21, 2009 3 min read by mkyong 16 comments

JUnit – Parameterized Test

In JUnit, you can pass the parameters into the unit test method via the following methods : Constructor Fields injection via @Parameter P.S Tested with JUnit 4.12 1. MatchUtils – Test with multiple parameters A simple add operation. MathUtils.java package com.mkyong.examples; public class MathUtils { public static int add(int a, int b) { return a […]

unit test May 21, 2009 1 min read by mkyong 19 comments

JUnit – Suite Test, run multiple test cases

In JUnit, you can run multiple test cases with @RunWith and @Suite annotation. Refer to the following examples : SuiteAbcTest.java package com.mkyong; import org.junit.Test; import org.junit.runner.RunWith; import org.junit.runners.Suite; @RunWith(Suite.class) @Suite.SuiteClasses({ Exception1Test.class, //test case 1 TimeoutTest.class //test case 2 }) public class SuiteAbcTest { //normally, this is an empty class } P.S Tested with JUnit 4.12 […]

unit test May 20, 2009 2 min read by mkyong 2 comments

JUnit – Timeout Test

If a test is taking longer than a defined “timeout” to finish, a TestTimedOutException will be thrown and the test marked failed. See the following example : P.S Tested with JUnit 4.12 1. Timeout Example This timeout example only applies to a single test method. And the timeout value is in milliseconds. TimeoutTest.java package com.mkyong; […]

unit test May 19, 2009 1 min read by mkyong 9 comments

JUnit – Ignore a Test

In JUnit, to ignore a test, just add a @Ignore annotation before or after the @Test method. P.S Tested with JUnit 4.12 IgnoreTest.java package com.mkyong; import org.junit.Ignore; import org.junit.Test; import static org.hamcrest.CoreMatchers.is; import static org.junit.Assert.assertThat; public class IgnoreTest { @Test public void testMath1() { assertThat(1 + 1, is(2)); } @Ignore @Test public void testMath2() { […]

unit test May 18, 2009 3 min read by mkyong 8 comments

JUnit – Expected Exceptions Test

In JUnit, there are 3 ways to test the expected exceptions : @Test, optional ‘expected’ attribute Try-catch and always fail() @Rule ExpectedException P.S Tested with JUnit 4.12 1. @Test expected attribute Use this if you only want to test the exception type, refer below : Exception1Test.java package com.mkyong; import org.junit.Test; import java.util.ArrayList; public class Exception1Test […]

unit test May 17, 2009 1 min read by mkyong 32 comments

JUnit – Basic annotation examples

Here’re some basic JUnit annotations you should understand: @BeforeClass – Run once before any of the test methods in the class, public static void @AfterClass – Run once after all the tests in the class have been run, public static void @Before – Run before @Test, public void @After – Run after @Test, public void […]

unit test May 16, 2009 4 min read by mkyong 23 comments

TestNG – Dependency Test

In TestNG, we use dependOnMethods and dependsOnGroups to implement dependency testing. If a dependent method is fail, all the subsequent test methods will be skipped, NOT failed. 1. dependOnMethods Example A simple example, “method2()” is dependent on “method1()”. 1.1 If method1() is passed, method2() will be executed. App.java package com.mkyong.testng.examples.dependency; import org.testng.annotations.Test; public class App […]

unit test May 15, 2009 6 min read by mkyong 15 comments

TestNG – Parameter Test (XML and @DataProvider)

In this tutorial, we will show you how to pass parameters into a @Test method, via XML @Parameters or @DataProvider. 1. Passing Parameters with XML In this example, the properties filename is passing from testng.xml, and inject into the method via @Parameters. TestParameterXML.java package com.mkyong.testng.examples.parameter; import java.io.IOException; import java.io.InputStream; import java.sql.Connection; import java.sql.DriverManager; import java.util.Properties; […]

unit test May 14, 2009 5 min read by mkyong 21 comments

TestNG – Run multiple test classes (suite test)

In this tutorial, we will show you how to run multiple TestNG test cases (classes) together, aka suite test. 1. Test Classes Review following three test classes. TestConfig.java package com.mkyong.testng.examples.suite; import org.testng.annotations.AfterSuite; import org.testng.annotations.AfterTest; import org.testng.annotations.BeforeSuite; import org.testng.annotations.BeforeTest; //show the use of @BeforeSuite and @BeforeTest public class TestConfig { @BeforeSuite public void testBeforeSuite() { System.out.println("testBeforeSuite()"); […]

web development May 14, 2009 1 min read by mkyong 7 comments

JQuery hit Internet Explorer ActiveX controls warning? – Solution

The following code is a JQuery javascript which will refresh the captcha image automatically wherever user clicked on it. The code is working fine in FireFox. However, when i test it in Internet explorer 6 or 7, i hit the following Active X controls warning. Your security settings do not allow Web sites to use […]

unit test May 12, 2009 1 min read by mkyong 3 comments

TestNG – Timeout Test

In this tutorial, we will show you how to perform timeout test in TestNG. The “timeout” means if a unit test is taking longer than a specified number of milliseconds to finish, TestNG will abort it and market it as failed. This “timeout” can also use for performance test, to ensure the method is returned […]

maven May 12, 2009 2 min read by mkyong 62 comments

How to include custom library into maven local repository?

For Java libraries that are not available in the Maven Central or other Maven repositories, we need to install it into our Maven Local repository in order to use it as a project dependencies. Note You may interest at this How to add Oracle JDBC driver in your Maven local repository In this tutorial, we […]

unit test May 11, 2009 1 min read by mkyong 4 comments

TestNG – How to ignore a test method

In this tutorial, we will show you how to ignore a test method with @Test(enabled = false). TestIgnore.java package com.mkyong.testng.examples.ignore; import org.testng.Assert; import org.testng.annotations.Test; public class TestIgnore { @Test //default enable=true public void test1() { Assert.assertEquals(true, true); } @Test(enabled = true) public void test2() { Assert.assertEquals(true, true); } @Test(enabled = false) public void test3() { […]

unit test May 10, 2009 2 min read by mkyong 10 comments

TestNG – Expected Exception Test

In this tutorial, we will show you how to use the TestNG expectedExceptions to test the expected exception throws in your code. 1. Runtime Exception This example shows you how to test a runtime exception. If the method divisionWithException () throws a runtime exception – ArithmeticException, it will be passed. TestRuntime.java package com.mkyong.testng.examples.exception; import org.testng.annotations.Test; […]

unit test May 10, 2009 4 min read by mkyong 14 comments

TestNG – Configuration Annotations Example

In TestNG, we can use the following annotations to do the configuration for your test class, like setup / clean a database, preparing the dummy data, deploy / shut down the server and etc. @BeforeSuite – For suite test, run before all tests in this suite have run. @AfterSuite – For suite test, run after […]

java May 4, 2009 2 min read by mkyong 11 comments

How to detect OS in Java

This article shows a handy Java class that uses System.getProperty("os.name") to detect which type of operating system (OS) you are using now. 1. Detect OS (Original Version) This code can detect Windows, Mac, Unix, and Solaris. OSValidator.java package com.mkyong.system; public class OSValidator { private static String OS = System.getProperty("os.name").toLowerCase(); public static void main(String[] args) { […]

hudson May 4, 2009 1 min read by mkyong 0 comments

PMD error – Can’t use JDK 1.5 for loop syntax when running in JDK 1.4 mode!

When i integrate Hudson and PMD together to run the PMD static code analysis process in my web project. I hit the following error message. By the way , i’m using Maven 2 to mange my web project. Caused by: net.sourceforge.pmd.ast.ParseException: Can’t use JDK 1.5 for loop syntax when running in JDK 1.4 mode! at […]

css April 30, 2009 1 min read by mkyong 2 comments

CSS Padding property setting

CSS Padding property setting is confusing sometime, because it can accept 1 value, 2 values , 3 or 4 values together. For example, all the padding property setting below is valid. padding: 10px; padding: 10px 8px; padding: 10px 8px 10px; padding: 10px 8px 10px 9px; CSS Padding Rule. 1) CSS padding order is follow clockwise […]

java April 28, 2009 2 min read by mkyong 16 comments

How to read a UTF-8 file in Java

In Java, the InputStreamReader accepts a charset to decode the byte streams into character streams. We can pass a StandardCharsets.UTF_8 into the InputStreamReader constructor to read data from a UTF-8 file. import java.nio.charset.StandardCharsets; //… try (FileInputStream fis = new FileInputStream(file); InputStreamReader isr = new InputStreamReader(fis, StandardCharsets.UTF_8); BufferedReader reader = new BufferedReader(isr) ) { String str; […]

java April 28, 2009 2 min read by mkyong 8 comments

How to write a UTF-8 file in Java

In Java, the OutputStreamWriter accepts a charset to encode the character streams into byte streams. We can pass a StandardCharsets.UTF_8 into the OutputStreamWriter constructor to write data to a UTF-8 file. try (FileOutputStream fos = new FileOutputStream(file); OutputStreamWriter osw = new OutputStreamWriter(fos, StandardCharsets.UTF_8); BufferedWriter writer = new BufferedWriter(osw)) { writer.append(line); } In Java 7+, many […]

javascript April 24, 2009 1 min read by mkyong 27 comments

focus() is not working in IE ? – solution

The focus() method is used to give focus to a textbox, or other html components. Here is a simple example to make a textbox focus automatically after page load. focus is not working in IE The above code is working fine in Firefox (FF), but not in Internet Explorer (IE). Actually the IE is supporting […]

javascript April 24, 2009 1 min read by mkyong 17 comments

How to get element by name in HTML – getElementsByName

The getElementsByName() method is use to get the element by name. However be aware of the getElementsByName() method always return an array as output. Caution The method always return an array, and we have to use [] to access the value. For example alert(document.getElementsByName(“myInput”).value); It will prompt out an undefined value alert(document.getElementsByName(“myInput”)[0].value); It will prompt […]

java April 23, 2009 1 min read by mkyong 7 comments

How to suppress unchecked warnings – Java

The ‘unchecked warnings’ is quite popular warning message in Java. However, if you insist this is an invalid warning, and there are no ways to solve it without compromising the existing program functionality. You may just use @SuppressWarnings(“unchecked”) to suppress unchecked warnings in Java. 1. In Class If applied to class level, all the methods […]

java April 22, 2009 1 min read by mkyong 4 comments

How to insert a new line in resource bundle messages – java

Here is a simple ResourceBundle message files hello = "Hi \n \n Good Morning \n \n thanks" If we retrieve the resource bundle key “hello”, we expected the result as following Hi Good Morning thanks Unfortunately, Java doesn’t work in this way, “String” will not translate the \n into new line by default. If we […]

javascript April 17, 2009 1 min read by mkyong 3 comments

How to get div id element in Javascript

In JavaScript, you can use getElementById() fucntion to get any prefer HTML element by providing their tag id. Here is a HTML example to show the use of getElementById() function to get the DIV tag id, and use InnerHTML() function to change the text dynamically. HTML… <html> <head> <title>getElementById example</title> <script type="text/javascript"> function changeText(text) { […]

web development April 14, 2009 1 min read by mkyong 7 comments

How to get context-param value in java?

The “context-param” tag is define in “web.xml” file and it provides parameters to the entire web application. For example, store administrator’s email address in “context-param” parameter to send errors notification from our web application. web.xml <context-param> <param-name>AdministratorEmail</param-name> <param-value>[email protected]</param-value> </context-param> We can get the above “AdministratorEmail” context-param value with the following java code. String email= getServletContext().getInitParameter("AdministratorEmail"); […]

maven April 13, 2009 2 min read by mkyong 27 comments

Maven – How to skip unit test

In Maven, you can define a system property -Dmaven.test.skip=true to skip the entire unit test. By default, when building project, Maven will run the entire unit tests automatically. If any unit tests is failed, it will force Maven to abort the building process. In real life, you may STILL need to build your project even […]

java April 11, 2009 1 min read by mkyong 11 comments

How to encode a URL string or form parameter in java

This is always advisable to encode URL or form parameters; plain form parameter is vulnerable to cross site attack, SQL injection and may direct our web application into some unpredicted output. A URL String or form parameters can be encoded using the URLEncoder class – static encode (String s, String enc) method. For example, when […]

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