Email Manager Demo

A ready-to-run demonstration of the AppJars Email Manager — an AppJar that adds e-mail management to a Vaadin Flow application: composing messages with recipients, CC and BCC, an HTML or plain-text body and attachments, holding them in a send queue, delivering them over SMTP, and keeping a full audit trail of every delivery attempt.

It runs entirely on your machine on a file-based H2 database, with no login and nothing to configure. The e-mail list arrives pre-populated with sample messages in every delivery state, so every feature is one click away the moment the application starts.

The demo opens on a public landing page that summarizes the features and offers a guided tour of the e-mail view.

Visit the official AppJars documentation for more information.

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What you get out of the box

On first run the application seeds twelve sample e-mails (and leaves them alone on later restarts — the seeding only happens when the list is empty). The set deliberately covers every delivery status and every content type the AppJar supports, so nothing has to be set up before you can try an action:

Status	Count	What they demonstrate
Created	5	Drafts you can send, queue, edit or delete — including one with CC and BCC, an HTML announcement, and one carrying a PDF attachment
Send pending	2	Sitting in the delivery queue, picked up by the background sender on its next run
Sent	3	Already delivered, dated in the past — one plain text, one HTML, one with a CSV attachment
Send failed	2	Carry a captured failure reason you can inspect with Show error details, then retry

The sample set lives in EmailGenerator if you want to change what gets seeded.

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Prerequisites

• Java 21+
• Maven 3.8+
• Docker and Docker Compose — optional, only to watch mail actually arrive (see step 2)

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1. Run the application

mvn

(spring-boot:run is the default goal.) Then open http://localhost:8080. No login is required.

2. Watch mail arrive (optional)

Docker is not required. Without it every feature works as described, except that a send has nowhere to go: the e-mail lands in the Send failed.

To see messages actually delivered, start the throwaway SMTP server that ships with the demo:

docker compose up -d

That runs Mailpit — an SMTP server on port 1025 that captures everything sent to it instead of relaying it anywhere, with a web inbox on http://localhost:8025. The spring.mail.* properties already point at it.

Send an e-mail from the demo, wait for the sender task to fire, and the message shows up in the inbox, attachments and all.

You can start it before or after the application — no restart needed either way.

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Using the demo

The e-mail list

The Emails view is the whole AppJar in one screen. Every message is listed with its sender, subject, delivery status and creation date, and a colored status badge tells you where it stands:

Badge	Meaning
Created	A draft that has not been sent yet
Send pending	Queued, waiting for the background sender
Sent	Handed over to the SMTP server
Send failed	Delivery failed; the reason can be inspected

Filter the list by address, subject or status to narrow it down. On narrow screens the filters move behind a button.

Composing

Create opens the compose dialog, where everything an e-mail needs is set in one place: the From address (picked from the configured senders), the Recipients, Carbon copy and Blind carbon copy lists, the Subject and Body, a Send as HTML toggle that switches the body from plain text to HTML, and Attachments you upload and can remove again.

Saving stores the e-mail as Created — sending is a separate, deliberate action on the list.

Per-row actions

Each row carries an actions menu; which options it offers depends on the e-mail's status:

Action	What it does
View	Opens the e-mail read-only
Send now	Sends it immediately
Add to queue / Remove from send queue	Hands it to the background sender, or takes it back
Edit Email	Changes any of its fields
Delete	Removes the e-mail, after a confirmation
Show error details	Inspects the captured failure reason (failed e-mails only)
Preview HTML	Renders an HTML body as the recipient will see it (HTML e-mails only)

The delivery queue

Queued e-mails are sent by a background task on a cron schedule. The demo runs it every 10 seconds (email.task.cronexpression): add an e-mail to the queue, watch its badge flip to Sent, and — with Mailpit running — find it in the inbox.

Guided tour

The landing page and the navbar both carry a Guided tour menu. The tour highlights the real elements of the e-mail view and explains them one popover at a time, opening the compose dialog and a row's actions menu along the way so you see them as a user does:

Step	Covers
The e-mail list	The grid, its columns and the sample data
Delivery status	What each of the four status badges means
Search & filter	Filtering by address, subject or status
Compose a new e-mail	The button that opens the dialog — the tour continues inside it
The compose dialog	From, recipients, subject and body, the Send as HTML toggle, attachments and Save
Per-row actions	Every action a row can offer, and when it offers it
Free mode	The daily send quota and the Emails sent today counter

Leave the tour at any step with Esc or by clicking outside the popover.

Free mode

This demo runs unlicensed, which caps it at 5 successfully sent e-mails per day; the Emails sent today counter above the grid tracks the quota. Beyond the cap an e-mail stays queued instead of being sent. Every other feature is fully functional and unlimited — a full licence removes the cap and changes nothing else.

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Configuration

All configuration lives in src/main/resources/application.properties. Every AppJar property is documented in the Email Manager README.

Mail sender

These values match the bundled Mailpit container, which takes no credentials and speaks no TLS. Pointing the demo at a real relay means filling in the username and password and turning auth and STARTTLS back on.

Property	What it configures	Value in this demo
spring.mail.host	SMTP host	localhost
spring.mail.port	SMTP port	1025
spring.mail.protocol	Transport protocol	smtp
spring.mail.username	User to authenticate as	empty
spring.mail.password	Password to authenticate with	empty
spring.mail.properties.mail.smtp.auth	Whether the relay requires authentication	false
spring.mail.properties.mail.smtp.starttls.enable	Upgrade the connection with STARTTLS	false

Email Manager

Property	What it configures	Value in this demo
com.appjars.emailmanager.from	Sender addresses offered in the compose dialog. One address makes the field read-only; several turn it into a picker	example@example.com
email.task.cronexpression	How often the background sender drains the queue	0/10 * * * * * (every 10s)

Email Manager defaults left untouched

Not set by the demo, listed because they shape what the compose dialog accepts:

Property	What it configures	AppJar default
com.appjars.emailmanager.url.views.emailcrudview	Route the e-mail list is registered under	em/list
com.appjars.emailmanager.attachments.max-size	Largest attachment accepted, in bytes	26214400 (25 MB)
com.appjars.emailmanager.attachments.max-files	Attachments accepted per e-mail	5
com.appjars.emailmanager.attachments.accepted-types	Allow-list of attachment content types; empty accepts any	common document, image and archive types

Database

The demo uses a file-based H2 database under data/, so what you compose survives a restart. Delete that folder to start over from the seeded sample set.

Property	What it configures	Value in this demo
spring.datasource.url	JDBC URL of the H2 file database	jdbc:h2:./data/emailmanagerdemo;FILE_LOCK=NO
spring.datasource.driverClassName	JDBC driver	org.h2.Driver
spring.datasource.username / .password	Datasource credentials	sa / empty
spring.jpa.database-platform	Hibernate dialect	org.hibernate.dialect.H2Dialect
spring.h2.console.enabled	Serves the H2 web console at /h2-console	true

JPA / Hibernate

Property	What it configures	Value in this demo
spring.jpa.hibernate.ddl-auto	Schema generation strategy	update
spring.jpa.generate-ddl	Whether Spring generates the schema	true
spring.jpa.show-sql	Logs the SQL Hibernate issues	false
spring.jpa.properties.hibernate.format_sql	Pretty-prints that SQL when enabled	true

Uploads and UI

Property	What it configures	Value in this demo
spring.servlet.multipart.max-file-size	Largest file the servlet container accepts	100MB
spring.servlet.multipart.max-request-size	Largest total upload request	100MB
vaadin.i18n.provider	Vaadin i18n provider supplying the translations	com.appjars.utils.i18n.AppjarsI18nProvider

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Stopping the SMTP server

docker compose down

Captured mail is not persisted, so nothing is left behind.