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Java client version

The current Java client version is v4.1.2.

Breaking changes introduced in v4

The package and import paths have been updated from technology.semi.weaviate to io.weaviate.

See the Migration Guide for more info.

Installation and setup​

To get the latest stable version of the Java client library, add this dependency to your project:

<dependency>
  <groupId>io.weaviate</groupId>
  <artifactId>client</artifactId>
  <version>4.0.0</version>  <!-- Check latest version -->
</dependency>

This API client is compatible with Java 8 and beyond.

You can use the client in your project as follows:

package io.weaviate;

import io.weaviate.client.Config;
import io.weaviate.client.WeaviateClient;
import io.weaviate.client.base.Result;
import io.weaviate.client.v1.misc.model.Meta;

public class App {
  public static void main(String[] args) {
    Config config = new Config("http", "localhost:8080");
    WeaviateClient client = new WeaviateClient(config);
    Result<Meta> meta = client.misc().metaGetter().run();
    if (meta.getError() == null) {
      System.out.printf("meta.hostname: %s\n", meta.getResult().getHostname());
      System.out.printf("meta.version: %s\n", meta.getResult().getVersion());
      System.out.printf("meta.modules: %s\n", meta.getResult().getModules());
    } else {
      System.out.printf("Error: %s\n", meta.getError().getMessages());
    }
  }
}

Authentication​

For more comprehensive information on configuring authentication with Weaviate, refer to the authentication page.

The Java client offers multiple options for authenticating against Weaviate, including multiple OIDC authentication flows.

The suitable authentication options and methods for the client largely depend on the specific configuration of the Weaviate instance.

WCS authentication​

WCS + Weaviate client

Each Weaviate instance in Weaviate Cloud Services (WCS) is pre-configured to act as a token issuer for OIDC authentication.

See our WCS authentication documentation for instructions on how to authenticate against WCS with your preferred Weaviate client.

API key authentication​

Available in Weaviate Java client versions 4.0.2 and higher.

To authenticate against Weaviate using an API key, instantiate the client as follows:

import io.weaviate.client.Config;
import io.weaviate.client.WeaviateAuthClient;

Config config = new Config("https", "some-endpoint.weaviate.network");
WeaviateClient client = WeaviateAuthClient.apiKey(config, "YOUR-WEAVIATE-API-KEY");  // Replace w/ your Weaviate instance API key

OIDC authentication​

To authenticate against Weaviate with OIDC, you must select a flow made available by the identity provider and create the flow-specific authentication configuration.

This configuration will then be used by the Weaviate client to authenticate. The configuration includes secrets that help the client obtain an access token and, if configured, a refresh token.

The access token is added to the HTTP header of each request and is utilized for authentication with Weaviate. Typically, this token has a limited lifespan, and the refresh token can be employed to obtain a new set of tokens when necessary.

Resource Owner Password Flow​

This OIDC flow uses the username and password to obtain required tokens for authentication.

Note that not every provider automatically includes a refresh token and an appropriate scope might be required that depends on your identity provider. The client uses offline_access as the default scope. This works with some providers, but as it depends on the configuration of the identity providers, we ask you to refer to the identity provider's documentation.

Without a refresh token, there is no possibility to acquire a new access token and the client becomes unauthenticated after expiration.

note

The Weaviate client does not save the username or password used.

They are only used to obtain the first tokens, after which existing tokens will be used to obtain subsequent tokens if possible.

import io.weaviate.client.Config;
import io.weaviate.client.WeaviateAuthClient;

Config config = new Config("http", "weaviate.example.com:8080");
WeaviateAuthClient.clientPassword(
    config,
    "Your user",
    "Your password",
    Arrays.asList("scope1", "scope2") // optional, depends on the configuration of your identity provider (not required with WCS)
);

Client Credentials flow​

This OIDC flow uses a client secret to obtain required tokens for authentication.

This flow is recommended for server-to-server communication without end-users and authenticates an application to Weaviate. This authentication flow is typically regarded as more secure than the resource owner password flow: a compromised client secret can be simply revoked, whereas a compromised password may have larger implications beyond the scope of breached authentication.

To authenticate a client secret most identity providers require a scope to be specified. This scope depends on the configuration of the identity providers, so we ask you to refer to the identity provider's documentation.

Most providers do not include a refresh token in their response so client secret is saved in the client to obtain a new access token on expiration of the existing one.

import io.weaviate.client.Config;
import io.weaviate.client.WeaviateAuthClient;

Config config = new Config("http", "weaviate.example.com:8080");
WeaviateAuthClient.clientCredentials(
    config,
    "your_client_secret",
    Arrays.asList("scope1" ,"scope2") // optional, depends on the configuration of your identity provider
);

Refresh Token flow​

Any other OIDC authentication method can be used to obtain tokens directly from your identity provider, for example by using this step-by-step guide of the hybrid flow.

If no refresh token is provided, there is no possibility to obtain a new access token and the client becomes unauthenticated after expiration.

import io.weaviate.client.Config;
import io.weaviate.client.WeaviateAuthClient;

Config config = new Config("http", "weaviate.example.com:8080");
WeaviateAuthClient.bearerToken(
    config,
    "Your_access_token",
    500,  // lifetime in seconds
    "Your_refresh_token",
);

Custom headers​

You can pass custom headers to the client, which are added at initialization:

import io.weaviate.client.Config;
import io.weaviate.client.WeaviateClient;

public class App {
  public static void main(String[] args) {
    Map<String, String> headers = new HashMap<String, String>() { {
      put("header_key", "value");
    } };
    Config config = new Config("http", "localhost:8080", headers);
    WeaviateClient client = new WeaviateClient(config);
  }
}

References​

All RESTful endpoints and GraphQL functions references covered by the Java client, and explained on those reference pages in the code blocks.

Design​

Builder pattern​

The Java client functions are designed with a 'Builder pattern'. A pattern is used to build complex query objects. This means that a function (for example to retrieve data from Weaviate with a request similar to a RESTful GET request, or a more complex GraphQL query) is built with single objects to reduce complexity. Some builder objects are optional, others are required to perform specific functions. All is documented on the RESTful API reference pages and the GraphQL reference pages.

The code snippet above shows a simple query similar to RESTful GET /v1/meta. The client is initiated by requiring the package and connecting to the running instance. Then, a query is constructed by using the .metaGetter() on .misc(). The query will be sent with the .run() function, this object is thus required for every function you want to build and execute.

Migration Guides​

From 3.x.x to 4.0.0​

Moved from technology.semi.weaviate to io.weaviate package​

Before:

package technology.semi.weaviate;
import technology.semi.weaviate.client.*;

After:

package io.weaviate;
import io.weaviate.client.*;

From 2.4.0 to 3.0.0​

Removed @Deprecated method Aggregate::withFields(Fields fields)​

Before:

// import io.weaviate.client.v1.graphql.query.fields.Field;
// import io.weaviate.client.v1.graphql.query.fields.Fields;

Fields fields = Fields.builder().fields(new Field[]{name, description}).build();
client.graphQL().aggregate().withFields(fields)...

After:

client.graphQL().aggregate().withFields(name, description)...

Removed @Deprecated method Get::withFields(Fields fields)​

Before:

// import io.weaviate.client.v1.graphql.query.fields.Field;
// import io.weaviate.client.v1.graphql.query.fields.Fields;

Fields fields = Fields.builder().fields(new Field[]{name, description}).build();
client.graphQL().get().withFields(fields)...

After:

client.graphQL().get().withFields(name, description)...

Removed @Deprecated method Get::withNearVector(Float[] vector)​

Before:

client.graphQL().get().withNearVector(new Float[]{ 0f, 1f, 0.8f })...

After:

// import io.weaviate.client.v1.graphql.query.argument.NearVectorArgument;

NearVectorArgument nearVector = NearVectorArgument.builder().vector(new Float[]{ 0f, 1f, 0.8f }).certainty(0.8f).build();
client.graphQL().get().withNearVector(nearVector)...

All where filters use the same implementation​

With batch delete feature, unified filters.WhereFilter implementation is introduced, which replaces classifications.WhereFilter, graphql.query.argument.WhereArgument and graphql.query.argument.WhereFilter.

GraphQL​

Before:

// import io.weaviate.client.v1.graphql.query.argument.GeoCoordinatesParameter;
// import io.weaviate.client.v1.graphql.query.argument.WhereArgument;
// import io.weaviate.client.v1.graphql.query.argument.WhereOperator;

GeoCoordinatesParameter geo = GeoCoordinatesParameter.builder()
    .latitude(50.51f)
    .longitude(0.11f)
    .maxDistance(3000f)
    .build();
WhereArgument where = WhereArgument.builder()
    .valueGeoRange(geo)
    .operator(WhereOperator.WithinGeoRange)
    .path(new String[]{ "add "})
    .build();

client.graphQL().aggregate().withWhere(where)...

After:

// import io.weaviate.client.v1.filters.Operator;
// import io.weaviate.client.v1.filters.WhereFilter;

WhereFilter where = WhereFilter.builder()
    .valueGeoRange(WhereFilter.GeoRange.builder()
        .geoCoordinates(WhereFilter.GeoCoordinates.builder()
            .latitude(50.51f)
            .longitude(0.11f)
            .build()
        )
        .distance(WhereFilter.GeoDistance.builder()
            .max(3000f)
            .build()
        )
        .build()
    )
    .operator(Operator.WithinGeoRange)
    .path(new String[]{ "add" })
    .build();

client.graphQL().aggregate().withWhere(where)...

Before:

// import io.weaviate.client.v1.graphql.query.argument.WhereArgument;
// import io.weaviate.client.v1.graphql.query.argument.WhereOperator;

WhereArgument where = WhereArgument.builder()
    .valueString("txt")
    .operator(WhereOperator.Equal)
    .path(new String[]{ "add" })
    .build();

client.graphQL().aggregate().withWhere(where)...

After:

// import io.weaviate.client.v1.filters.Operator;
// import io.weaviate.client.v1.filters.WhereFilter;

WhereFilter where = WhereFilter.builder()
    .valueString("txt")
    .operator(Operator.Equal)
    .path(new String[]{ "add" })
    .build();

client.graphQL().aggregate().withWhere(where)...

Before:

// import io.weaviate.client.v1.graphql.query.argument.WhereArgument;
// import io.weaviate.client.v1.graphql.query.argument.WhereFilter;
// import io.weaviate.client.v1.graphql.query.argument.WhereOperator;

WhereArgument where = WhereArgument.builder()
    .operands(new WhereFilter[]{
        WhereFilter.builder()
            .valueInt(10)
            .path(new String[]{ "wordCount" })
            .operator(WhereOperator.LessThanEqual)
            .build(),
        WhereFilter.builder()
            .valueString("word")
            .path(new String[]{ "word" })
            .operator(WhereOperator.LessThan)
            .build()
    })
    .operator(WhereOperator.And)
    .build();

client.graphQL().aggregate().withWhere(where)...

After:

// import io.weaviate.client.v1.filters.Operator;
// import io.weaviate.client.v1.filters.WhereFilter;

WhereFilter where = WhereFilter.builder()
    .operands(new WhereFilter[]{
        WhereFilter.builder()
            .valueInt(10)
            .path(new String[]{ "wordCount" })
            .operator(Operator.LessThanEqual)
            .build(),
        WhereFilter.builder()
            .valueString("word")
            .path(new String[]{ "word" })
            .operator(Operator.LessThan)
            .build(),
    })
    .operator(Operator.And)
    .build();

client.graphQL().aggregate().withWhere(where)...
Classification​

Before:

// import io.weaviate.client.v1.classifications.model.GeoCoordinates;
// import io.weaviate.client.v1.classifications.model.Operator;
// import io.weaviate.client.v1.classifications.model.WhereFilter;
// import io.weaviate.client.v1.classifications.model.WhereFilterGeoRange;
// import io.weaviate.client.v1.classifications.model.WhereFilterGeoRangeDistance;

WhereFilter where = WhereFilter.builder()
    .valueGeoRange(WhereFilterGeoRange.builder()
        .geoCoordinates(GeoCoordinates.builder()
            .latitude(50.51f)
            .longitude(0.11f)
            .build())
        .distance(WhereFilterGeoRangeDistance.builder()
            .max(3000d)
            .build())
        .build())
    .operator(Operator.WithinGeoRange)
    .path(new String[]{ "geo" })
    .build();

client.classifications().scheduler().withTrainingSetWhereFilter(where)...

After:

// import io.weaviate.client.v1.filters.Operator;
// import io.weaviate.client.v1.filters.WhereFilter;

WhereFilter where = WhereFilter.builder()
    .valueGeoRange(WhereFilter.GeoRange.builder()
        .geoCoordinates(WhereFilter.GeoCoordinates.builder()
            .latitude(50.51f)
            .longitude(0.11f)
            .build())
        .distance(WhereFilter.GeoDistance.builder()
            .max(3000f)
            .build())
        .build())
    .operator(Operator.WithinGeoRange)
    .path(new String[]{ "geo" })
    .build();

client.classifications().scheduler().withTrainingSetWhereFilter(where)...

Change logs​

Check the change logs on GitHub for updates on the latest Java client changes.

More Resources​

If you can't find the answer to your question here, please look at the:

  1. Frequently Asked Questions. Or,
  2. Knowledge base of old issues. Or,
  3. For questions: Stackoverflow. Or,
  4. For more involved discussion: Weaviate Community Forum. Or,
  5. We also have a Slack channel.