Sending Email in Java

There are various ways to send email using JavaMail API. For this purpose, you must have SMTP server that is responsible to send mails.

You can use one of the following techniques to get the SMTP server:

• Install and use any SMTP server such as Postcast server, Apache James server, cmail server etc. (or)
• Use the SMTP server provided by the host provider e.g. my SMTP server is mail.javatpoint.com (or)
• Use the SMTP Server provided by other companies e.g. gmail etc.

Here, we are going to learn above three approaches to send email using javamail API. But we should learn the basic steps to send email from java application.

Steps to send email using JavaMail API

There are following three steps to send email using JavaMail. They are as follows:

1. Get the session object that stores all the information of host like host name, username, password etc.
2. compose the message
3. send the message

1) Get the session object

The javax.mail.Session class provides two methods to get the object of session, Session.getDefaultInstance() method and Session.getInstance() method. You can use any method to get the session object.

Method of Session class

No.	Method	Description
1	public static Session getDefaultInstance(Properties props)	returns the default session.
2	public static Session getDefaultInstance(Properties props,Authenticator auth)	returns the default session.
3	public static Session getInstance(Properties props)	returns the new session.
4	public static Session getInstance(Properties props,Authenticator auth)	returns the new session.

Example of getDefaultInstance() method

1. Properties properties=new Properties();  
2. //fill all the information like host name etc.  
3. Session session=Session.getDefaultInstance(properties,null);  

Example of getInstance() method

1. Properties properties=new Properties();  
2. //fill all the information like host name etc.  
3. Session session=Session.getInstance(properties,null);  

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2) Compose the message

The javax.mail.Message class provides methods to compose the message. But it is an abstract class so its subclass javax.mail.internet.MimeMessage class is mostly used.

To create the message, you need to pass session object in MimeMessage class constructor. For example:

1. MimeMessage message=new MimeMessage(session);  

Now message object has been created but to store information in this object MimeMessage class provides many methods. Let's see methods provided by the MimeMessage class:

Commonly used methods of MimeMessage class

No.	Method	Description
1	public void setFrom(Address address)	is used to set the from header field.
2	public void addRecipient(Message.RecipientType type, Address address)	is used to add the given address to the recipient type.
3	public void addRecipients(Message.RecipientType type, Address[] addresses)	is used to add the given addresses to the recipient type.
4	public void setSubject(String subject)	is used to set the subject header field.
5	public void setText(String textmessage)	is used to set the text as the message content using text/plain MIME type.
6	public void setContent(Object msg, String contentType)	is used to set the content as the message content using given MIME type.

Example to compose the message:

1. MimeMessage message=new MimeMessage(session);  
2. message.setFrom(new InternetAddress("sonoojaiswal@sssit.org"));  
3. message.addRecipient(Message.RecipientType.To,   
4. new InternetAddress("sonoojaiswal@javatpoint.com"));  
5. message.setHeader("Hi, everyone");  
6. message.setText("Hi, This mail is to inform you...");  

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3) Send the message

The javax.mail.Transport class provides method to send the message.

Commonly used methods of Transport class

No.	Method	Description
1	public static void send(Message message)	is used send the message.
2	public static void send(Message message, Address[] address)	is used send the message to the given addresses.

Example to send the message:

1. Transport.send(message);  

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Simple example of sending email in Java

In this example, we are going to learn how to send email by SMTP server installed on the machine e.g. Postcast server, Apache James server, Cmail server etc. If you want to send email by using your SMTP server provided by the host provider, see the example after this one.

For sending the email using JavaMail API, you need to load the two jar files: mail.jar activation.jar download these jar files or go to the Oracle site to download the latest version.

1. import java.util.*;  
2. import javax.mail.*;  
3. import javax.mail.internet.*;  
4. import javax.activation.*;  
5.   
6. public class SendEmail  
7. {  
8.  public static void main(String [] args){  
9.       String to = "sonoojaiswal1988@gmail.com";//change accordingly  
10.       String from = "sonoojaiswal1987@gmail.com";change accordingly  
11.       String host = "localhost";//or IP address  
12.   
13.      //Get the session object  
14.       Properties properties = System.getProperties();  
15.       properties.setProperty("mail.smtp.host", host);  
16.       Session session = Session.getDefaultInstance(properties);  
17.   
18.      //compose the message  
19.       try{  
20.          MimeMessage message = new MimeMessage(session);  
21.          message.setFrom(new InternetAddress(from));  
22.          message.addRecipient(Message.RecipientType.TO,new InternetAddress(to));  
23.          message.setSubject("Ping");  
24.          message.setText("Hello, this is example of sending email  ");  
25.   
26.          // Send message  
27.          Transport.send(message);  
28.          System.out.println("message sent successfully....");  
29.   
30.       }catch (MessagingException mex) {mex.printStackTrace();}  
31.    }  
32. }  

In this example, we are going to learn how to send email by SMTP server installed on the machine e.g. Postcast server, Apache James server, Cmail server etc. If you want to send email by using your SMTP server provided by the host provider, see the example after this one.

To run this example, you need to load two jar files. There are 4 ways to load the jar file. One of the way is set classpath. Let's see how to run this example:

Load the jar file	c:\> set classpath=mail.jar;activation.jar;.;
compile the source file	c:\> javac SendEmail.java
run by	c:\> java SendEmail

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Example of sending email in Java through SMTP server provided by the host provider

If you are using the SMTP server provided by the host provider e.g. mail.javatpoint.com , you need to authenticate the username and password. The javax.mail.PasswordAuthentication class is used to authenticate the password.

If you are sending the email using JavaMail API, load the two jar files: mail.jar activation.jar download these jar files or go to the Oracle site to download the latest version.

1. import java.util.Properties;  
2. import javax.mail.*;  
3. import javax.mail.internet.*;  
4.   
5. public class SendMailBySite {  
6.  public static void main(String[] args) {  
7.   
8.   String host="mail.javatpoint.com";  
9.   final String user="sonoojaiswal@javatpoint.com";//change accordingly  
10.   final String password="xxxxx";//change accordingly  
11.     
12.   String to="sonoojaiswal1987@gmail.com";//change accordingly  
13.   
14.    //Get the session object  
15.    Properties props = new Properties();  
16.    props.put("mail.smtp.host",host);  
17.    props.put("mail.smtp.auth", "true");  
18.      
19.    Session session = Session.getDefaultInstance(props,  
20.     new javax.mail.Authenticator() {  
21.       protected PasswordAuthentication getPasswordAuthentication() {  
22.     return new PasswordAuthentication(user,password);  
23.       }  
24.     });  
25.   
26.    //Compose the message  
27.     try {  
28.      MimeMessage message = new MimeMessage(session);  
29.      message.setFrom(new InternetAddress(user));  
30.      message.addRecipient(Message.RecipientType.TO,new InternetAddress(to));  
31.      message.setSubject("javatpoint");  
32.      message.setText("This is simple program of sending email using JavaMail API");  
33.        
34.     //send the message  
35.      Transport.send(message);  
36.   
37.      System.out.println("message sent successfully...");  
38.    
39.      } catch (MessagingException e) {e.printStackTrace();}  
40.  }  
41. }  

As you can see in the above example, userid and password need to be authenticated. As this program illustrates, you can send email easily. Change the username and password accordingly. Let's see how to run it once again by simple technique:

Load the jar file	c:\> set classpath=mail.jar;activation.jar;.;
compile the source file	c:\> javac SendMailBySite.java
run by	c:\> java SendMailBySite