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Visualizing Training with DJL

This module provides training visualization UI and backend service.

Currently, implemented features:

  • Training/Validating progress
  • Training Metrics Visualization chart
  • Inference: Online image/Local image


  • You need to have Java Development Kit version 11 or later installed on your system.
  • You should be familiar with the API documentation in the DJL Javadoc.

Install the Java Development Kit

For ubuntu:

sudo apt-get install openjdk-11-jdk-headless

For centos:

sudo yum install java-11-openjdk-devel

For macOS:

brew tap homebrew/cask-versions
brew update
brew cask install adoptopenjdk11

You can also download and install Oracle JDK manually if you have trouble with the previous commands.

If you have multiple versions of Java installed, you can use the $JAVA_HOME environment variable to control which version of Java to use.

Getting started: 30 seconds to run an example

Build and install DJL UI

This component supports building with npm. To build, use the following command:
(Refer to reference info, if you encounter any issue.)

# clone the project
git clone

# Install npm if you didn't have npm installed
brew install npm

# enter the project directory
cd djl-demo/visualization-vue/djl-training-ui

# install dependency
npm install

# develop
npm run dev

This will automatically open http://localhost:8090

Build backend example project

To build, use the following command:

# enter the project directory
cd djl-demo/visualization-vue/djl-training-demo/

# Maven build
./mvnw package -DskipTests

# Run example code
java -jar target/djl-training-demo-0.0.1-SNAPSHOT.jar
# or
mvnw spring-boot:run

Open browser

Open http://localhost:8090 to get:

1. Training:


2. Inference:


Reference information

1. Check node.js and npm version:

node -v
npm -v

2. Install latest node.js and npm:

#Clean cache
sudo npm cache clean -f
#Install n
sudo npm install -g n
#Install latest node.js
sudo n stable
#Install latest npm
sudo npm install npm@latest -g

3. If you're getting this error on Mac OSX:

"Package pangocairo was not found in the pkg-config search path."
Ensure to run:

brew install pkg-config
brew intall cairo
brew install pango