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DJL Spark Image Classification Example


This folder contains two demo applications built with Spark and DJL to run a group image classification task.

  • ImageClassificationExample: Ready to run for classification using built in model in ModelZoo
  • DataProcessExample: If you are new to DJL and would like to learn more on the processing logic. (PyTorch Engine only)


We provide two options to build, you can choose to build with sbt or gradle.

We use PyTorch engine by default, you can switch to MXNet or TensorFlow Engine adding these lines:



libraryDependencies += "ai.djl.mxnet" % "mxnet-model-zoo" % "0.6.0"
libraryDependencies += "ai.djl.mxnet" % "mxnet-native-auto" % "1.7.0-a"


libraryDependencies += "ai.djl.tensorflow" % "tensorflow-model-zoo" % "0.6.0"
libraryDependencies += "ai.djl.tensorflow" % "tensorflow-native-auto" % "2.2.0"


You should add these in dependencies


runtimeOnly "ai.djl.mxnet:mxnet-model-zoo:0.6.0"
runtimeOnly "ai.djl.mxnet:mxnet-native-auto:1.7.0-a"


runtimeOnly "ai.djl.tensorflow:tensorflow-model-zoo:0.6.0"
runtimeOnly "ai.djl.tensorflow:tensorflow-native-auto:2.2.0"

Apart from that, you may also need to use NaiveEngine mode in MXNet for multi-thread inference. Please add this line in your SparkConf

.setExecutorEnv("MXNET_ENGINE_TYPE", "NaiveEngine")

Run the example

This example will run image classification with pretrained resnet18 model on images in the images folder. The output will be saved under out/spark_output.

This is the expected output from console:

    class: "n02085936 Maltese dog, Maltese terrier, Maltese", probability: 0.81445
    class: "n02096437 Dandie Dinmont, Dandie Dinmont terrier", probability: 0.08678
    class: "n02098286 West Highland white terrier", probability: 0.03561
    class: "n02113624 toy poodle", probability: 0.01261
    class: "n02113712 miniature poodle", probability: 0.01200
    class: "n02123045 tabby, tabby cat", probability: 0.52391
    class: "n02123394 Persian cat", probability: 0.24143
    class: "n02123159 tiger cat", probability: 0.05892
    class: "n02124075 Egyptian cat", probability: 0.04563
    class: "n03942813 ping-pong ball", probability: 0.01164
    class: "n03770679 minivan", probability: 0.95839
    class: "n02814533 beach wagon, station wagon, wagon, estate car, beach waggon, station waggon, waggon", probability: 0.01674
    class: "n03769881 minibus", probability: 0.00610
    class: "n03594945 jeep, landrover", probability: 0.00448
    class: "n03977966 police van, police wagon, paddy wagon, patrol wagon, wagon, black Maria", probability: 0.00278