Jeamlit Embedded

This method embeds Jeamlit as a dependency in your existing Maven or Gradle project. This method is best for complex apps, existing systems, and production deployments.

This page will walk you through adding Jeamlit to your Maven or Gradle project, creating a simple interactive app, and launching an embedded server. You'll build the same click counter app but with full control over the server lifecycle.

Prerequisites

As with any Java project, you'll need:

Java JDK >= 21

Download and install a Java JDK (we recommend Eclipse Adoptium).

You can verify your Java installation by running:

java --version
Maven or Gradle
- Maven: Download from maven.apache.org or use the Maven wrapper (mvnw) included in most projects
- Gradle: Download from gradle.org or use the Gradle wrapper (gradlew)
An IDE (recommended)

We recommend IntelliJ IDEA for the best hot-reload experience with Jeamlit.

Setup

With Maven

Add the Jeamlit dependency to your pom.xml:

<dependencies> <dependency> <groupId>io.jeamlit</groupId> <artifactId>jeamlit</artifactId> <version>0.44.0</version> </dependency>  <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-math3</artifactId> <version>3.6.1</version> </dependency>  <dependency> <groupId>ch.qos.logback</groupId> <artifactId>logback-classic</artifactId> <version>1.5.18</version> </dependency> </dependencies>
Make sure your pom.xml specifies Java 21:

<properties> <maven.compiler.source>21</maven.compiler.source> <maven.compiler.target>21</maven.compiler.target> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> </properties>

With Gradle

Add the Jeamlit dependency to your build.gradle:

dependencies { implementation 'io.jeamlit:jeamlit:0.44.0' // Optional: Add any other dependencies your app needs implementation 'org.apache.commons:commons-math3:3.6.1' // Recommended: Add a logging implementation implementation 'ch.qos.logback:logback-classic:1.5.18' }
Make sure your build.gradle specifies Java >= 21:

java { toolchain { languageVersion = JavaLanguageVersion.of(21) } }

Create your Jeamlit app

Create src/main/java/App.java with your Jeamlit application:

import io.jeamlit.core.Jt;
import org.apache.commons.math3.stat.descriptive.DescriptiveStatistics;

public class App {

    public static void main(String[] args) {
        Jt.title("Hello World !").use();

        Jt.markdown("## A simple click app").use();

        // initialize state - values in the session state are maintained at each update
        Jt.sessionState().putIfAbsent("count", 0);

        // if button is clicked, increment the count value
        if (Jt.button("Click me").use()) {
            Jt.sessionState().computeIfPresentInt("count", (k, v) -> v + 1);
        }

        // display the count
        int count = Jt.sessionState().getInt("count");
        boolean plural = count > 1;
        Jt.markdown("The button was clicked **%s** time%s".formatted(count, plural ? "s" : ""))
                .use();


        // Use the imported library apache commons-math
        Jt.divider().use();
        Jt.markdown("## Using imported apache math dependency").use();
        double[] values = {1.2, 2.3, 3.4, 4.5, 5.6};
        DescriptiveStatistics stats = new DescriptiveStatistics(values);
        double stdDev = stats.getStandardDeviation();
        Jt.text("Computed statistic with Apache commons-math: " + stdDev).use();
    }
}

Create src/main/java/Launcher.java to start the embedded server:

import io.jeamlit.core.Server;

public class Launcher {

    public static void main(String[] args) {
        final var server = Server.builder(App.class, 8080).build();
        server.start();
    }
}

Build and run

With Maven

Build your project:

./mvnw clean install
Run the Jeamlit server:

./mvnw compile exec:java -Dexec.mainClass="Launcher"
Open your browser at http://localhost:8080 to see your app!
To stop the server, press Ctrl+C in the terminal.

With Gradle

Build your project:

./gradlew build
Run the Jeamlit server:

./gradlew run --main-class=Launcher
Open your browser at http://localhost:8080 to see your app!
To stop the server, press Ctrl+C in the terminal.

Development with hot-reload

IntelliJ IDEA Setup

Open your project in IntelliJ IDEA
Run Launcher.java in Debug mode (not Run mode)
Open your browser at http://localhost:8080
Edit App.java and add some code, for example:
Jt.markdown("**OMG THE HOT-RELOAD IS REAL**").use();
When you see the "Code Change" modal in IntelliJ, click it to hot-reload
Refresh your browser to see the changes instantly!

What's next?

Read about our Basic concepts to understand Jeamlit's dataflow model

Previous: Standalone Next: Embedded in Spring

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Still have questions?

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