Sending an email using kotlin and javax.mail

ApacheMailer.kt

/*
 * Sending an email using kotlin and Apache Commons Email
 * 
 * Usage: java -jar app.jar <user> <password> <from> <to> <cc>
 */
package main.kotlin.sendmail

import org.apache.commons.mail.Email
import org.apache.commons.mail.EmailException
import org.apache.commons.mail.HtmlEmail
import java.util.*

// dependencies {
//     implementation 'org.apache.commons:commons-email:1.5'
// }

// <dependency>
//    <groupId>org.apache.commons</groupId>
//    <artifactId>commons-email</artifactId>
//    <version>1.5</version>
// </dependency>

fun main(args: Array<String>) {
    val userName = args[0]
    val password = args[1]
    // FYI: passwords as a command arguments isn't safe
    // They go into your bash/zsh history and are visible when running ps

    val emailFrom = args[2]
    val emailTo = args[3]
    val emailCC = args[4]

    val subject = "SMTP Test"
    val text = "Hello Kotlin Mail"

    try {
        val email: HtmlEmail = HtmlEmail()
        email.hostName = "smtp.office365.com"
        email.setSmtpPort(587)
        email.setAuthentication(userName, password)
        email.isSSLOnConnect = true
        email.setFrom(emailFrom)
        email.addTo(emailTo)
        email.addCc(emailCC)
        email.subject = subject
        email.setMsg(text)
        email.send()
        println("Sent message successfully....")
    } catch (emailException: EmailException) {
        emailException.printStackTrace()
    }
}

OracleMailer.kt

/*
 * Sending an email using kotlin and javax.mail (Oracle JDK)
 * 
 * Usage: java -jar app.jar <user> <password> <from> <to> <cc>
 */
package main.kotlin.sendmail

import java.util.*
import javax.mail.*
import javax.mail.internet.*

fun main(args: Array<String>) {
    val userName =  args[0]
    val password =  args[1]
    // FYI: passwords as a command arguments isn't safe
    // They go into your bash/zsh history and are visible when running ps

    val emailFrom = args[2]
    val emailTo = args[3]
    val emailCC = args[4]

    val subject = "SMTP Test"
    val text = "Hello Kotlin Mail"

    val props = Properties()
    putIfMissing(props, "mail.smtp.host", "smtp.office365.com")
    putIfMissing(props, "mail.smtp.port", "587")
    putIfMissing(props, "mail.smtp.auth", "true")
    putIfMissing(props, "mail.smtp.starttls.enable", "true")

    val session = Session.getDefaultInstance(props, object : javax.mail.Authenticator() {
        override fun getPasswordAuthentication(): PasswordAuthentication {
            return PasswordAuthentication(userName, password)
        }
    })

    session.debug = true

    try {
        val mimeMessage = MimeMessage(session)
        mimeMessage.setFrom(InternetAddress(emailFrom))
        mimeMessage.setRecipients(Message.RecipientType.TO, InternetAddress.parse(emailTo, false))
        mimeMessage.setRecipients(Message.RecipientType.CC, InternetAddress.parse(emailCC, false))
        mimeMessage.setText(text)
        mimeMessage.subject = subject
        mimeMessage.sentDate = Date()

        val smtpTransport = session.getTransport("smtp")
        smtpTransport.connect()
        smtpTransport.sendMessage(mimeMessage, mimeMessage.allRecipients)
        smtpTransport.close()
    } catch (messagingException: MessagingException) {
        messagingException.printStackTrace()
    }
}

private fun putIfMissing(props: Properties, key: String, value: String) {
    if (!props.containsKey(key)) {
        props[key] = value
    }
}

i am getting this error

java.lang.ClassNotFoundException: Didn't find class "java.awt.datatransfer.Transferable"

i am getting this error

java.lang.ClassNotFoundException: Didn't find class "java.awt.datatransfer.Transferable"

Oh weird... What jdk are you using?

Where to put to email, Thanks

javax.mail.* does not seem to be available in liberica-full-22. Which JRE or JDK were you using?

javax.mail.* does not seem to be available in liberica-full-22. Which JRE or JDK were you using?

I'm not 100% sure, probably Oracle's JDK, I made this in 2019. I wouldn't touch an Oracle JDK after 2020 when they started suing people. org.apache.commons:commons-email looks good though.

@BlackthornYugen I think with

implementation("jakarta.mail:jakarta.mail-api:2.1.3")
implementation("org.eclipse.angus:jakarta.mail:2.0.3")

...and its jakarta.mail.* classes is what you need today. javax.mail.* not part of the JDK anymore which is probably a good thing anyway.