java.mdx

title
Using with Java

This article describes how to use Apollo Kotlin in Java projects.

Use the Java codegen

Apollo Kotlin generates Kotlin code by default, but you can configure it to use the Java codegen instead:

apollo {
  service("service") {
    generateKotlinModels.set(false)
  }
}

Build the client

This snippet demonstrates initializing an ApolloClient instance in Java:

import com.apollographql.apollo3.cache.normalized.NormalizedCache;
import com.apollographql.apollo3.cache.http.HttpCache;
// (...)

ApolloClient.Builder builder = new ApolloClient.Builder()
  .serverUrl("http://localhost:4000/graphql")

// Optionally, set an http cache
HttpCache.configureApolloClientBuilder(builder, cacheDirectory, cacheMaxSize);

// Optionally, set a normalized cache
NormalizedCache.configureApolloClientBuilder(
  builder,
  new MemoryCacheFactory(10 * 1024 * 1024, -1),
  TypePolicyCacheKeyGenerator.INSTANCE,
  FieldPolicyCacheResolver.INSTANCE,
  false
);

ApolloClient client = builder.build();

Use RxJava extensions

Apollo Kotlin has a coroutines / Flow-based API that isn't well suited to using with Java. To achieve a similar effect, you can use Apollo's RxJava extensions.