import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.mail.SimpleMailMessage;

@EnableConfigurationProperties
public class MailSender
{
    @Autowired
    private static JavaMailSender mailSender;

    public static void main(String[] args)
    {
        send();
    }
    public static void send() {
        SimpleMailMessage message = new SimpleMailMessage();
        message.setFrom("abc@gmail.com");
        message.setTo("xyz@gmail.com");
        message.setSubject("hello");
        mailSender.send();
    }
}

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>Example</groupId>
    <artifactId>SendingEmail</artifactId>
    <version>1.0-SNAPSHOT</version>
    <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.3.2.RELEASE</version>
    </parent>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-mail</artifactId>
        </dependency>

        <dependency>
            <groupId>javax.mail</groupId>
            <artifactId>mail</artifactId>
            <version>1.4.5</version>
        </dependency>
    </dependencies>


</project>

spring.mail.host=smtp.gmail.com
spring.mail.username=*****
spring.mail.password=*****
spring.mail.properties.mail.smtp.auth = true
spring.mail.properties.mail.smtp.socketFactory.port = 25
spring.mail.properties.mail.smtp.socketFactory.class = javax.net.ssl.SSLSocketFactory
spring.mail.properties.mail.smtp.socketFactory.fallback = false
spring.mail.properties.mail.smtp.ssl.enable=true