Installing TensorFlow for Java

TensorFlow provides APIs for use in Java programs. These APIs are particularly well-suited to loading models created in Python and executing them within a Java application. This guide explains how to install TensorFlow for Java and use it in a Java application.

WARNING: The TensorFlow Java API is not covered by the TensorFlow API stability guarantees.

Supported Platforms

TensorFlow for Java is supported on the following operating systems:

• Linux
• Mac OS X
• Windows
• Android

The installation instructions for Android are in a separate Android TensorFlow Support page. After installation, please see this complete example of TensorFlow on Android.

Using TensorFlow with a Maven project

If your project uses Apache Maven, then add the following to the project's pom.xml to use the TensorFlow Java APIs:

<dependency>
  <groupId>org.tensorflow</groupId>
  <artifactId>tensorflow</artifactId>
  <version>1.3.0-rc1</version>
</dependency>

That's all.

Example

As an example, these steps will create a Maven project that uses TensorFlow:

1. Create the project's pom.xml:

     <project>
         <modelVersion>4.0.0</modelVersion>
         <groupId>org.myorg</groupId>
         <artifactId>hellotf</artifactId>
         <version>1.0-SNAPSHOT</version>
         <properties>
           <exec.mainClass>HelloTF</exec.mainClass>
           <!-- The sample code requires at least JDK 1.7. -->
           <!-- The maven compiler plugin defaults to a lower version -->
           <maven.compiler.source>1.7</maven.compiler.source>
           <maven.compiler.target>1.7</maven.compiler.target>
         </properties>
         <dependencies>
           <dependency>
             <groupId>org.tensorflow</groupId>
             <artifactId>tensorflow</artifactId>
             <version>1.3.0-rc1</version>
           </dependency>
         </dependencies>
     </project>

1. Create the source file (src/main/java/HelloTF.java):

    import org.tensorflow.Graph;
    import org.tensorflow.Session;
    import org.tensorflow.Tensor;
    import org.tensorflow.TensorFlow;

    public class HelloTF {
      public static void main(String[] args) throws Exception {
        try (Graph g = new Graph()) {
          final String value = "Hello from " + TensorFlow.version();

          // Construct the computation graph with a single operation, a constant
          // named "MyConst" with a value "value".
          try (Tensor t = Tensor.create(value.getBytes("UTF-8"))) {
            // The Java API doesn't yet include convenience functions for adding operations.
            g.opBuilder("Const", "MyConst").setAttr("dtype", t.dataType()).setAttr("value", t).build();
          }

          // Execute the "MyConst" operation in a Session.
          try (Session s = new Session(g);
               Tensor output = s.runner().fetch("MyConst").run().get(0)) {
            System.out.println(new String(output.bytesValue(), "UTF-8"));
          }
        }
      }
    }

1. Compile and execute:

    # Use -q to hide logging from the mvn tool
   mvn -q compile exec:java

The preceding command should output Hello from version. If it does, you've successfully set up TensorFlow for Java and are ready to use it in Maven projects. If not, check Stack Overflow for possible solutions. You can skip reading the rest of this document.

Using TensorFlow with JDK

This section describes how to use TensorFlow using the java and javac commands from a JDK installation. If your project uses Apache Maven, then refer to the simpler instructions above instead.

Install on Linux or Mac OS

Take the following steps to install TensorFlow for Java on Linux or Mac OS:

1. Download libtensorflow.jar, which is the TensorFlow Java Archive (JAR).

2. Decide whether you will run TensorFlow for Java on CPU(s) only or with the help of GPU(s). To help you decide, read the section entitled "Determine which TensorFlow to install" in one of the following guides:

   • Installing TensorFlow on Linux
   • Installing TensorFlow on Mac OS

3. Download and extract the appropriate Java Native Interface (JNI) file for your operating system and processor support by running the following shell commands:

     TF_TYPE="cpu" # Default processor is CPU. If you want GPU, set to "gpu"
     OS=$(uname -s | tr '[:upper:]' '[:lower:]')
     mkdir -p ./jni
     curl -L \
       "https://storage.googleapis.com/tensorflow/libtensorflow/libtensorflow_jni-${TF_TYPE}-${OS}-x86_64-1.3.0-rc1.tar.gz" |
       tar -xz -C ./jni

Install on Windows

Take the following steps to install TensorFlow for Java on Windows:

1. Download libtensorflow.jar, which is the TensorFlow Java Archive (JAR).
2. Download the following Java Native Interface (JNI) file appropriate for TensorFlow for Java on Windows.
3. Extract this .zip file.

Validate the installation

After installing TensorFlow for Java, validate your installation by entering the following code into a file named HelloTF.java:

import org.tensorflow.Graph;
import org.tensorflow.Session;
import org.tensorflow.Tensor;
import org.tensorflow.TensorFlow;

public class HelloTF {
  public static void main(String[] args) throws Exception {
    try (Graph g = new Graph()) {
      final String value = "Hello from " + TensorFlow.version();

      // Construct the computation graph with a single operation, a constant
      // named "MyConst" with a value "value".
      try (Tensor t = Tensor.create(value.getBytes("UTF-8"))) {
        // The Java API doesn't yet include convenience functions for adding operations.
        g.opBuilder("Const", "MyConst").setAttr("dtype", t.dataType()).setAttr("value", t).build();
      }

      // Execute the "MyConst" operation in a Session.
      try (Session s = new Session(g);
           Tensor output = s.runner().fetch("MyConst").run().get(0)) {
        System.out.println(new String(output.bytesValue(), "UTF-8"));
      }
    }
  }
}

And use the instructions below to compile and run HelloTF.java.

Compiling

When compiling a Java program that uses TensorFlow, the downloaded .jar must be part of your classpath. For example, you can include the downloaded .jar in your classpath by using the -cp compilation flag as follows:

javac -cp libtensorflow-1.3.0-rc1.jar HelloTF.java

Running

To execute a Java program that depends on TensorFlow, ensure that the following two files are available to the JVM:

• the downloaded .jar file
• the extracted JNI library

For example, the following command line executes the HelloTF program on Linux and Mac OS X:

java -cp libtensorflow-1.3.0-rc1.jar:. -Djava.library.path=./jni HelloTF

And the following command line executes the HelloTF program on Windows:

java -cp libtensorflow-1.3.0-rc1.jar;. -Djava.library.path=jni HelloTF

If the program prints Hello from version, you've successfully installed TensorFlow for Java and are ready to use the API. If the program outputs something else, check Stack Overflow for possible solutions.

Advanced Example

For a more sophisticated example, see LabelImage.java, which recognizes objects in an image.

Building from source code

TensorFlow is open-source. You may build TensorFlow for Java from the TensorFlow source code by following the instructions in a separate document.