There was a requirement of deleting multiple options from a listbox using JavaScript. User can select multiple items from a Listbox. Once the delete button is pressed, remove all the values that are selected from the combobox.

Now the most intuitive solution for this problem would be to iterate through each option from the listbox and delete it if it is selected. So one would write following piece of HTML & JavaScript.

The HTML

Define a simple listbox with id lsbox and two buttons, Delete & Reset.

<table>
<tr>
	<td align="center">
		<select id="lsbox" name="lsbox" size="10" multiple>
			<option value="1">India</option>
			<option value="2">United States</option>
			<option value="3">China</option>
			<option value="4">Italy</option>
			<option value="5">Germany</option>
			<option value="6">Canada</option>
			<option value="7">France</option>
			<option value="8">United Kingdom</option>
		</select>
	</td>
</tr>
<tr>
	<td align="center">
		<button onclick="listbox_remove('lsbox');">Delete</button>
		<button onclick="window.location.reload();">Reset</button>
	</td>
</tr>
</table>

Below is the JavaScript code.

The (Incorrect) JavaScript

function listbox_remove(sourceID) {

    //get the listbox object from id.
    var src = document.getElementById(sourceID);

    //iterate through each option of the listbox
    for(var count = 0; count < src.options.length; count--) {
         //if the option is selected, delete the option
        if(src.options[count].selected == true) {
                var option = src.options[count];

                try {
                         src.remove(count, null);

                 } catch(error) {

                         src.remove(count);
                }
        }
    }
}

That’s it right? Wait, this wont work correctly. Each time you delete an option using src.remove() method, the remaining option’s index will decrease by 1. So if you have selected multiple values to delete, this wont behave as you expected.

Check out the below demo:

Demo: The Incorrect Way

In following demo, we used the normal approach (above javascript) to remove the options.

So we know the problem now. Each time the value is deleted, the index of option is decremented. So the ideal approach must be to iterate through the options of listbox in opposite way. Thus we start with the last options and iterate till first.

The Correct JavaScript

Notice the loop at line: XX. We are iterating in opposite direction.

function listbox_remove(sourceID) {

    //get the listbox object from id.
    var src = document.getElementById(sourceID);

    //iterate through each option of the listbox
    for(var count= src.options.length-1; count >= 0; count--) {

         //if the option is selected, delete the option
        if(src.options[count].selected == true) {
                var option = src.options[count];

                try {
                         src.remove(count, null);

                 } catch(error) {

                         src.remove(count);
                }
        }
    }
}

Following is the demo with correct JavaScript.

Demo: The Correct Way

In following demo, we used the correct approach (javascript) to remove the values.

Hope this helps!

Download Source Code

Delete_Multiple_Values_Listbox.zip (1.2 KB)

When you are writing a piece of code from scratch a lot of time you do silly mistakes and still wonder why its not working. Well same thing happened the other day when I added a Hibernate Entity class in one project and was struggling to make it work.

The exception was:

org.hibernate.AnnotationException: No identifier specified for entity: net.viralpatel.hibernate.Employee
	at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:650)
	at org.hibernate.cfg.AnnotationConfiguration.processArtifactsOfType(AnnotationConfiguration.java:498)
	at org.hibernate.cfg.AnnotationConfiguration.secondPassCompile(AnnotationConfiguration.java:277)
	at org.hibernate.cfg.Configuration.buildMappings(Configuration.java:1112)
	at org.hibernate.ejb.Ejb3Configuration.buildMappings(Ejb3Configuration.java:1269)
	at org.hibernate.ejb.EventListenerConfigurator.configure(EventListenerConfigurator.java:150)
	at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:888)
	at org.hibernate.ejb.Ejb3Configuration.configure(Ejb3Configuration.java:416)
	at org.hibernate.ejb.HibernatePersistence.createContainerEntityManagerFactory(HibernatePersistence.java:126)
	at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:227)
	at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:273)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1367)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1333)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:471)
	at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory$1.run(AbstractAutowireCapableBeanFactory.java:409)
	at java.security.AccessController.doPrivileged(Native Method)

The error here is that in your Entity class, you have not defined a primary key. Thus specify either @Id annotation or an @EmbeddedId annotation.

So if you have an entity class Employee like below:

package net.viralpatel.hibernate;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Table;

@Entity
@Table(name="EMPLOYEE")
public class Employee {

    @Column(name="employee_id")
    private Long employeeId;

    @Column(name="firstname")
    private String firstname;

    @Column(name="lastname")
    private String lastname;

    //Getter and Setter methods	

}

And if you try to execute this, it will generate exception org.hibernate.AnnotationException: No identifier specified for entity: net.viralpatel.hibernate.Employee

So the solution is just add @Id to appropriate primary key column.

package net.viralpatel.hibernate;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Table;
import javax.persistence.Id;

@Entity
@Table(name="EMPLOYEE")
public class Employee {

    @Id
    @Column(name="employee_id")
    private Long employeeId;

    @Column(name="firstname")
    private String firstname;

    @Column(name="lastname")
    private String lastname;

    //Getter and Setter methods	

}

Thus every class defined as Entity with @Entity annotation, needs an @Id or @EmbeddedId property.

Hope that helps and reduce your debugging effort.

While working on an Android App, I had to integrate the Camera API. User can take a photo from App and process it. With Android the Photo that you click cannot be accessed until the media scanner runs and index it. It is possible to triggeer programatically the Media Scanner in Android. Check the below code snippet:

import android.content.Intent;
import android.net.Uri;
import android.os.Environment;
...
...
sendBroadcast( new Intent(Intent.ACTION_MEDIA_MOUNTED,
						Uri.parse("file://" + Environment.getExternalStorageDirectory()))
			);
...

Here we are using sendBroadcast method from Activity class to send a broadcast message to an Intent. For our need we have used ACTION_MEDIA_MOUNTED intent which will invoke the media scanner. Also note that we have passed the path (URI) of our external storage directory.

So in your app whenever you want to trigger Media scanner, simply invoke the above intent via broadcast message.

Following is a Demo App to achieve this.

Demo App

The App will be very simple. It will have a button “Trigger Media Scanner”. On its click we will invoke the above sendBroadcast() code to trigger media scanner.

Step 1: Create Basic Android Project in Eclipse

Create a Hello World Android project in Eclipse. Go to New > Project > Android Project. Give the project name as MediaScannerDemo and select Android Runtime 2.1 or sdk 7. I have given package name net.viralpatel.android.mediascanner.

Once you are done with above steps, you will have a basic hello world Android App.

Step 2: Change the Layout

For our demo, we need simple layout. Just one button Trigger Image Scanner which does the job.

Open layout/main.xml in your android project and replace its content with following:

File: res/layout/main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:gravity="center">

    <Button
    		android:id="@+id/buttonMediaScanner"
    		android:layout_width="fill_parent"
    		android:text="Trigger Media Scanner"
    		android:textSize="25dp"
    		android:layout_height="100dp"></Button>

</LinearLayout>

The UI is very simply. One LinearLayout to organize the button and one button. Note the id for button buttonMediaScanner which we will use in our Java code.

Step 3: Android Java Code to trigger Image Scanner Intent

Open MediaScannerDemoActivity class and add following code in OnCreate() method.

package net.viralpatel.android.mediascanner;

import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;

public class MediaScannerDemoActivity extends Activity {
	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		Button buttonMediaScanner = (Button) findViewById(R.id.buttonMediaScanner);

		//Add onClick event on Media scanner button
		buttonMediaScanner.setOnClickListener(new OnClickListener() {

			@Override
			public void onClick(View view) {

				//Broadcast the Media Scanner Intent to trigger it
				sendBroadcast(new Intent(Intent.ACTION_MEDIA_MOUNTED, Uri
						.parse("file://"
								+ Environment.getExternalStorageDirectory())));

				//Just a message
				Toast toast = Toast.makeText(getApplicationContext(),
						"Media Scanner Triggered...", Toast.LENGTH_SHORT);
				toast.show();
			}
		});

	}
}

Thus in OnCreate() method, we have added an OnClickListener to button. In the listener class, we added logic to trigger media scanner and also a Toast message to show user that scanner has been triggered.

Screen shots of Android App

And that’s all! Just execute the app in Android emulator or real device and see following output.

On click of Trigger Media Scanner button, the media scanner is invoked which we can see in Title bar.

Download Source Code

MediaScannerDemo.zip (45 KB)

By default when you create an Android Virtual Devices (AVD) in Android, the Camera is disabled. So if your application uses Camera API, it might not work properly in Android Emulator. Also SDCard must be defined in emulator in order to use Camera.

To enable Camera in your Android Emulator, just add following highlighted code in your AVD’s config.ini file. You can find the config.ini file under your user directory/.android folder.

File: ~/.android/config.ini

hw.lcd.density=160
skin.name=HVGA
skin.path=platforms\android-9\skins\HVGA
hw.cpu.arch=arm
abi.type=armeabi
vm.heapSize=24
image.sysdir.1=platforms\android-9\images\
hw.camera=yes
sdcard.size=64M
...
...

In case you don’t find the config.ini file or want to enable Camera support through Android SDK and AVD Manager, follow below simple steps.

Open Android SDK and AVD Manager:

Step 1: Add SD Card in AVD

In the SD Card setting, set the value for Size. To enable camera, the SD Card must be enabled in Emulator.

Step 2: Add Camera Support in Hardware under AVD

Now under Hardware section, click New button to add Camera hardware. It will open following Dialog box. Select Camera support from the Property dropdown and click Ok.

Step 3: Enable Camera Support in Hardware

The new hardware: Camera support is visible under Hardware section. Set its value to yes and save changes by pressing Edit AVD.

And that’s all. Just save the changes and launch the emulator. You’ll be able to start Camera application and take snaps (Default android pic) through it.

Today almost every website you visit show content in form of thumbnails. Thumbnails are nothing but images displayed next to the content. Be it News website or a blog, displaying images next to content is key to appeal user. Even our blog shows images as thumbnails on home page.

A prerequisites to show Thumbnail in a webpage is that thumbnail must be small enough. So that many thumbnails can be loaded as fast as possible. Hence almost every website resize the image to create small thumbnails.

So how to do this on the fly? How to resize an Image dynamically in PHP?

There is an extremely useful PHP library called timthumb which comes very handy. It’s just a simple PHP script that you need to download and put in some folder under your website. And then simply call it with appropriate arguments.

1. Download timthumb.php and put under any folder.
2. Upload this script timthumb.php though FTP to your web hosting. Put it under a directory /script.
3. Just call timthumb.php with appropriate arguments, For example:

   <img src="/script/timthumb.php?src=/some/path/myimage.png&w=100&h=80"
   	alt="resized image" />
   

And that’s all!!

One thing worth noting here is that this library will create a folder cache in the directory where timthumb.php script resides. This folder will cache the resized image for better performance.

You can refer following table for different parameters and its meaning.

Hope this is useful for you

Since few days I am working on an Android app and learning all the nitty gritty of its APIs. I will share few How-to stuffs that we frequently require in Android.

To start with let us see how to integrate Image Gallery with your App. Consider a requirement, you want your app user to select Image from the Gallery and use that image to do some stuff. For example, in Facebook app you can select Picture from your phone and upload directly to your profile.

Let us create an example with following requirement:

1. First screen shows user with and Image view and a button to loan Picture.
2. On click of “Load Picture” button, user will be redirected to Android’s Image Gallery where she can select one image.
3. Once the image is selected, the image will be loaded in Image view on main screen.

So lets start.

Step 1: Create Basic Android Project in Eclipse

Create a Hello World Android project in Eclipse. Go to New > Project > Android Project. Give the project name as ImageGalleryDemo and select Android Runtime 2.1 or sdk 7.

Once you are done with above steps, you will have a basic hello world Android App.

Step 2: Change the Layout

For our demo, we need simple layout. One Image view to display user selected image and one button to trigger Image gallery.

Open layout/main.xml in your android project and replace its content with following:

File: res/layout/main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent">
	<ImageView
		android:id="@+id/imgView"
		android:layout_width="fill_parent"
		android:layout_height="wrap_content"
		android:layout_weight="1"></ImageView>
	<Button
		android:id="@+id/buttonLoadPicture"
		android:layout_width="wrap_content"
		android:layout_height="wrap_content"
		android:layout_weight="0"
		android:text="Load Picture"
		android:layout_gravity="center"></Button>
</LinearLayout>

So our Android’s app UI is very simple, One LinearLayout to organize Image view and Button linearly. Note that the id of Image view is imgView and that of Button is buttonLoadPicture.

Step 3: Android Java Code to trigger Image Gallery Intent

We now need to write some Java code to actually handle the button click. On click of buttonLoadPicture button, we need to trigger the intent for Image Gallery.

Thus, on click of button we will trigger following code:

	Intent i = new Intent(
	Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

	startActivityForResult(i, RESULT_LOAD_IMAGE);

Note how we passed an integer RESULT_LOAD_IMAGE to startActivityForResult() method. This is to handle the result back when an image is selected from Image Gallery.

So the above code will trigger Image Gallery. But how to retrieve back the image selected by user in our main activity?

Step 4: Getting back selected Image details in Main Activity

Once user will select an image, the method onActivityResult() of our main activity will be called. We need to handle the data in this method as follows:

   @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    	super.onActivityResult(requestCode, resultCode, data);

		if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && null != data) {
			Uri selectedImage = data.getData();
			String[] filePathColumn = { MediaStore.Images.Media.DATA };

			Cursor cursor = getContentResolver().query(selectedImage,
					filePathColumn, null, null, null);
			cursor.moveToFirst();

			int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
			String picturePath = cursor.getString(columnIndex);
			cursor.close();

			// String picturePath contains the path of selected Image
		}

Note that method onActivityResult gets called once an Image is selected. In this method, we check if the activity that was triggered was indeed Image Gallery (It is common to trigger different intents from the same activity and expects result from each). For this we used RESULT_LOAD_IMAGE integer that we passed previously to startActivityForResult() method.

Final Code

Below is the final code of ImageGalleryDemoActivity class.

package net.viralpatel.android.imagegalleray;

import android.app.Activity;
import android.content.Intent;
import android.database.Cursor;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class ImageGalleryDemoActivity extends Activity {

	private static int RESULT_LOAD_IMAGE = 1;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Button buttonLoadImage = (Button) findViewById(R.id.buttonLoadPicture);
        buttonLoadImage.setOnClickListener(new View.OnClickListener() {

			@Override
			public void onClick(View arg0) {

				Intent i = new Intent(
						Intent.ACTION_PICK,
						android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

				startActivityForResult(i, RESULT_LOAD_IMAGE);
			}
		});
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    	super.onActivityResult(requestCode, resultCode, data);

		if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && null != data) {
			Uri selectedImage = data.getData();
			String[] filePathColumn = { MediaStore.Images.Media.DATA };

			Cursor cursor = getContentResolver().query(selectedImage,
					filePathColumn, null, null, null);
			cursor.moveToFirst();

			int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
			String picturePath = cursor.getString(columnIndex);
			cursor.close();

			ImageView imageView = (ImageView) findViewById(R.id.imgView);
			imageView.setImageBitmap(BitmapFactory.decodeFile(picturePath));

		}

    }
}

Screen shots of Android app

First screen: Lets user to trigger Image Gallery

User can select an image from Image Gallery

Once user selects an image, the same will be displayed on our main activity

Download Source Code

ImageGalleryDemo.zip (46 KB)

In this short article we will see how to iterate an HashMap in FreeMarker template. Consider below code which is normally used to iterate a List in FTL.

//Java
List<String> cityList = new ArrayList<String>();
cityList.add("Washington DC");
cityList.add("Delhi");
cityList.add("Berlin");
cityList.add("Paris");
cityList.add("Rome");

request.setAttribute("cityList", cityList);

//FTL template
<#list cityList as city>
    <b> ${city} </b>
</#list>

Output:

Washington DC
Delhi
Berlin
Paris
Rome

Here in above code, we created a List object and passed it to FTL page. In FTL we used <#list> to iterate and print its values.

Problem Statement

So here’s the problem statement. I have an Hashmap which I want to iterate and display in my FTL (FreeMarker) template. Consider following code in Java.

So how to iterate this Hashmap in FTL and display its values?

//Java
Map<String, String> countryCapitalList = new HashMap<String, String>();
countryCapitalList.put("United States", "Washington DC");
countryCapitalList.put("India", "Delhi");
countryCapitalList.put("Germany", "Berlin");
countryCapitalList.put("France", "Paris");
countryCapitalList.put("Italy", "Rome");

request.setAttribute("capitalList", countryCapitalList);

Solution

Well, the above hashmap can be iterated in FTL using following code:

<#list capitalList?keys as key>
    ${key} = ${capitalList[key]}
</#list>

Output:

United States = Washington DC
India = Delhi
Germany = Berlin
France = Paris
Italy = Rome

In above code, we used ?keys attribute to get the keySet of HashMap. This key set is iterated and corresponding value is fetched by user.get(key) method.

Note: One thing that’s worth noting here is that the sequence in which the values are printing may be different then the actual sequence in which values are added in hashmap. This is because, hashmap doesn’t preserve order or values. If you want to preserve the sequence of keys use LinkedHashMap.

Hope this helps.

Let’s see how we can perform batch insert in Java using JDBC APIs. Although you might already knew this, I will try to explain the basic to a bit complex scenarios.

In this note, we will see how we can use JDBC APIs like Statement and PreparedStatement to insert data in any database in batches. Also we will try to explore scenarios where we can run out of memory and how to optimize the batch operation.

So first, the basic API to Insert data in database in batches using Java JDBC.

Simple Batch

I am calling this a simple batch. The requirement is simple. Execute a list of inserts in batch. Instead of hitting database once for each insert statement, we will using JDBC batch operation and optimize the performance.

Consider the following code:

Bad Code

String [] queries = {
	"insert into employee (name, city, phone) values ('A', 'X', '123')",
	"insert into employee (name, city, phone) values ('B', 'Y', '234')",
	"insert into employee (name, city, phone) values ('C', 'Z', '345')",
};

Connection connection = new getConnection();
Statement statemenet = connection.createStatement();

for (String query : queries) {
	statemenet.execute(query);
}
statemenet.close();
connection.close();

This is the BAD code. You are executing each query separately. This hits the database for each insert statement. Consider if you want to insert 1000 records. This is not a good idea.

We’ll below is the basic code to perform batch insert. Check it out:

Good Code

Connection connection = new getConnection();
Statement statemenet = connection.createStatement();

for (String query : queries) {
	statemenet.addBatch(query);
}
statemenet.executeBatch();
statemenet.close();
connection.close();

Note how we used addBatch() method of Statement, instead of directly executing the query. And after adding all the queries we executed them in one go using statement.executeBatch() method. Nothing fancy, just a simple batch insert.

Note that we have taken the queries from a String array. Instead you may want to make it dynamically. For example:

import java.sql.Connection;
import java.sql.Statement;

//...

Connection connection = new getConnection();
Statement statemenet = connection.createStatement();

for (Employee employee: employees) {
	String query = "insert into employee (name, city) values('"
			+ employee.getName() + "','" + employee.getCity + "')";
	statemenet.addBatch(query);
}
statemenet.executeBatch();
statemenet.close();
connection.close();

Note how we are creating query dynamically using data from Employee object and adding it in batch to insert in one go. Perfect! isn’t it?

wait.. You must be thinking what about SQL Injection? Creating queries like this dynamically is very prone to SQL injection. And also the insert query has to be compiled each time.

Why not to use PreparedStatement instead of simple Statement. Yes, that can be the solution. Check out the below SQL Injection Safe Batch.

SQL Injection Safe Batch

Consider the following code:

import java.sql.Connection;
import java.sql.PreparedStatement;

//...

String sql = "insert into employee (name, city, phone) values (?, ?, ?)";
Connection connection = new getConnection();
PreparedStatement ps = connection.prepareStatement(sql);

for (Employee employee: employees) {

	ps.setString(1, employee.getName());
	ps.setString(2, employee.getCity());
	ps.setString(3, employee.getPhone());
	ps.addBatch();
}
ps.executeBatch();
ps.close();
connection.close();

Checkout the above code. Beautiful. We used java.sql.PreparedStatement and added insert query in the batch. This is the solution you must implement in your batch insert logic, instead of above Statement one.

Still there is one problem with this solution. Consider a scenario where you want to insert half million records into database using batch. Well, that may generate OutOfMemoryError:

java.lang.OutOfMemoryError: Java heap space
    com.mysql.jdbc.ServerPreparedStatement$BatchedBindValues.<init>(ServerPreparedStatement.java:72)
    com.mysql.jdbc.ServerPreparedStatement.addBatch(ServerPreparedStatement.java:330)
    org.apache.commons.dbcp.DelegatingPreparedStatement.addBatch(DelegatingPreparedStatement.java:171)

This is because you are trying to add everything in one batch and inserting once. Best idea would be to execute batch itself in batch. Check out the below solution.

Smart Insert: Batch within Batch

This is a simplest solution. Consider a batch size like 1000 and insert queries in the batches of 1000 queries at a time.

String sql = "insert into employee (name, city, phone) values (?, ?, ?)";
Connection connection = new getConnection();
PreparedStatement ps = connection.prepareStatement(sql);

final int batchSize = 1000;
int count = 0;

for (Employee employee: employees) {

	ps.setString(1, employee.getName());
	ps.setString(2, employee.getCity());
	ps.setString(3, employee.getPhone());
	ps.addBatch();

	if(++count % batchSize == 0) {
		ps.executeBatch();
	}
}
ps.executeBatch(); // insert remaining records
ps.close();
connection.close();

This would be the idea solution. This avoids SQL Injection and also takes care of out of memory issue. Check how we have incremented a counter count and once it reaches batchSize which is 1000, we call executeBatch().

Hope this helps.

Java Collection API is one of the most useful APIs used in any Java application. In my day to day Java coding routine, I have to deal with these APIs quite often.

However sometime while working with Collection API, lot of developers end up writing unnecessary and mostly inefficient code. For example, to convert an Java Array to ArrayList, I have seen people writing loops instead of simple Arrays.asList().

Here is a simple writeup on Converting Java Arrays to ArrayList that I wrote a while ago.

One of such simple requirement is to convert Java Arrays to Set. While working with Hibernate, I once had to convert a Java Arrays that we used to populate from UI and convert it into Set. While this is a simple task, most often one may end up writing for loop.

Here is a dead simple trick. Use below code to Convert Arrays to Set in Java.

Set<T> mySet = new HashSet<T>(Arrays.asList(someArray));

Tanaa!!! Simple isn’t it. Its like “I already knew that” stuff.

Notice how we have used Generics also in above code snippet. Thus if you have an ArrayList than you can convert it to Set with one simple line of code.

Checkout below example:

Example: Java Array to Set

String [] countires = {"India", "Switzerland", "Italy"}; 

Set<String> set = new HashSet<String>(Arrays.asList(countires));
System.out.println(set);

Output:

[Italy, Switzerland, India]

Hope this is useful.

Right now, Internet is experiencing the biggest protest since its inception. We have seen people protesting against Companies, Government, Dictators etc. Also Internet has become their voices in form of Twitter & Facebook.

But today we saw something completely new. Major websites such as Wikipedia and Google are openly demonstrating their protest against new legislation bills SOPA and PIPA which is right now being voted in U.S. Congress. The Senate will begin voting on January 24th.

Well, if you do support the STOPSOPA cause here is a coolest thing to do. Add a black colored STOPSOPA banner on your website!!!!

Here’s is the deal. I have created a simple JQuery plugin which you can include at the end of your website. And voila!!! It adds black color banner on top of your webpage saying “I support #STOPSOPA campaign. Do you?”

Just include below javascript at the end of webpage:

<script type="text/javascript" src="http://viralpatel.net/stopsopa/jquery.stopsopa.js"></script>
<script>
	$(document).ready(function() { $(this).stopsopa() });
</script>

That’s All!!

Please note that I haven’t tested this plugin for cross browsers. Let me know in case you find difficulties in adding.

StopSOPA WordPress Plugin

I have quickly assemble a small wordpress plugin to add StopSOPA message on your blog. Just in case you dont want to hack your lovely theme and add those javascripts, you can simply enable this plugin and voila; you have your own StopSOPA Blackout message.

Update: The StopSOPA plugin is now available at WordPress Plugin Directory: StopSOPA WP Plugin