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Migrating Between TensorFlow Java Releases

TensorFlow Java is still in an alpha stage, therefore is subject to contain breaking changes between the different releases. This guide explain in detail how to migrate your code from a previous version to a new one that includes some changes that are not backward compatible.

Migrating to 1.0.0

TensorFlow-Java 1.0.0 requires Java 11 or later.

Native Artifact Renaming

The native artifacts, that used to be distributed as tensorflow-core-api, are now distributed under tensorflow-core-native. If you still add tensorflow-core-platform in your project, that won't affect you. But if you were adding dependencies to specific native runtimes, you need to update them to reflect the new artifact name.

For example,

<dependency>
    <groupId>org.tensorflow</groupId>
    <artifactId>tensorflow-core-api</artifactId>
    <version>0.5.0</version>
</dependency>
<dependency>
    <groupId>org.tensorflow</groupId>
    <artifactId>tensorflow-core-api</artifactId>
    <version>0.5.0</version>
    <classifier>linux-x86_64</classifier>
</dependency>

will now be

<dependency>
    <groupId>org.tensorflow</groupId>
    <artifactId>tensorflow-core-api</artifactId>
    <version>1.0.0</version>
</dependency>
<dependency>
    <groupId>org.tensorflow</groupId>
    <artifactId>tensorflow-core-native</artifactId>
    <version>1.0.0</version>
    <classifier>linux-x86_64</classifier>
</dependency>

Session Run Result

In versions before 0.4.0 Session.Runner.run and TensorFunction.call returned a List<Tensor>. In newer versions they return a Result class which is AutoCloseable to make management of the tensor lifetime simpler. To migrate users should wrap the run invocation in a try-with-resources statement rather than closing the output tensors individually.

Proto Definitions Moved

Some proto definitions under org.tensorflow.proto have been moved to a different location under the same package. You will need to reimport these proto bindings to match the new location. Your IDE should easily be able to do this for you.

Migrating to 0.3.0

Non-parameterized Typed Tensors

In previous versions, the Tensor class was parameterized with its tensor type interface, which is part of the TType family. To access directly the memory tensor from the JVM, an explicit conversion between Tensor and its tensor type was required by calling tensor.data().

In 0.3.0, tensors are always typed, making this generic parameter and explicit mapping obsolete. As soon as you get a handle to a tensor, you are able to access directly its memory for reading (or writing for most tensor types) and no convertion is required. Any instances of a class in the TType family can also now be manipulated directly as a Tensor (e.g. to be passed to a session for inference).

Steps:

  1. Replace a parameterized Tensor by its parameter (e.g. Tensor<TFloat32> -> TFloat32)
  2. Replace instance of Tensor<?> with unknown parameter by Tensor
  3. Remove any invocation to Tensor.data() (e.g. tensor.data().getFloat() -> tensor.getFloat())
  4. Replace any invocation to Operand.data() by Operand.asTensor()

Use of Java Type System instead of DataType

In previous versions, the DataType class was used to carry information about the type of a Tensor, that can then be converted back to a tensor of that type (see previous section). Since there were a exact parity between interfaces of the TType family and an instance of DataType, the latter has been dropped in 0.3.0 to leverage instead the standard type system in Java, for a better idiomatic experience.

Steps:

  1. Replace all accesses to the DTYPE field of a TType interface by its class (e.g. TFloat32.DTYPE -> TFloat32.class)
  2. Use Java type system for checking tensor types at runtime (e.g. using instanceof or isAssignableFrom)
  3. Replace any invocation to Tensor.expect() by an explicit cast (e.g. tensor.expect(TFloat32.DTYPE) -> (TFloat32)tensor)

Example

0.2.0:

Session session = ...;

try (Tensor<TFloat32> tensor = TFloat32.tensorOf(Shape.of(1, 2))) {
    TFloat32 tensorData = tensor.data();
    tensorData.setFloat(10.0f, 0);
    tensorData.setFloat(20.0f, 1);
    
    try (Tensor<?> result = session.runner().feed("x", tensor).fetch("y").run().get(0)) {
        if (result.dataType() == TFloat32.DTYPE) {
            Tensor<TFloat32> typedResult = result.expect(TFloat32.DTYPE);
            TFloat32 resultData = typedResult.data();
            System.out.println("Result is " + resultData.getFloat());
        }
    }
}

0.3.0:

Session session = ...;

try (TFloat32 tensor = TFloat32.tensorOf(Shape.of(1, 2))) {
    tensor.setFloat(10.0f, 0);
    tensor.setFloat(20.0f, 1);
    
    try (Tensor result = session.runner().feed("x", tensor).fetch("y").run().get(0)) {
        if (result instanceof TFloat32) {
            TFloat32 typedResult = (TFloat32)result;
            System.out.println("Result is " + typedResult.getFloat());
        }
    }
}