Java: Update to Service registry pattern (#1923)

Resolves #1628 

Also setKernelConfig -> withKernelConfig, to be in keeping with other
builder functions

java/api-test/api-usage-example/src/main/java/InlineFunctionExample.java

@@ -107,7 +107,7 @@ public class InlineFunctionExample {
                         .addTextCompletionService(MODEL, kernel -> textCompletion)
                         .build();
 
-        Kernel kernel = SKBuilders.kernel().setKernelConfig(kernelConfig).build();
+        Kernel kernel = SKBuilders.kernel().withKernelConfig(kernelConfig).build();
 
         CompletionSKFunction summarize =
                 kernel.getSemanticFunctionBuilder()

java/api-test/api-usage-example/src/main/java/InlineFunctionWithPreBuiltSkillExample.java

@@ -108,7 +108,7 @@ public class InlineFunctionWithPreBuiltSkillExample {
                         .addTextCompletionService(MODEL, kernel -> textCompletion)
                         .build();
 
-        Kernel kernel = SKBuilders.kernel().setKernelConfig(kernelConfig).build();
+        Kernel kernel = SKBuilders.kernel().withKernelConfig(kernelConfig).build();
 
         CompletionSKFunction summarize =
                 SKBuilders.completionFunctions(kernel)

java/api-test/integration-tests/src/test/java/com/microsoft/semantickernel/e2e/AbstractKernelTest.java

@@ -41,7 +41,7 @@ public class AbstractKernelTest {
                         .build();
 
         return SKBuilders.kernel()
-                .setKernelConfig(kernelConfig)
+                .withKernelConfig(kernelConfig)
                 .withMemoryStore(new VolatileMemoryStore())
                 .build();
     }

java/api-test/integration-tests/src/test/java/com/microsoft/semantickernel/e2e/KernelTest.java

@@ -57,7 +57,7 @@ public class KernelTest extends AbstractKernelTest {
                         .addTextCompletionService(model, kernel -> textCompletion)
                         .build();
 
-        return SKBuilders.kernel().setKernelConfig(kernelConfig).build();
+        return SKBuilders.kernel().withKernelConfig(kernelConfig).build();
     }
 
     @Test

java/samples/sample-code/src/main/java/com/microsoft/semantickernel/Example00_GettingStarted.java

@@ -36,7 +36,7 @@ public class Example00_GettingStarted {
                 .build();
 
         Kernel kernel = SKBuilders.kernel()
-                .setKernelConfig(config)
+                .withKernelConfig(config)
                 .build();
 
         return kernel;

java/samples/sample-code/src/main/java/com/microsoft/semantickernel/Example06_MemoryAndEmbeddings.java

@@ -16,7 +16,7 @@ public class Example06_MemoryAndEmbeddings {
     // TODO: Add Volatile memory
 
     Kernel kernel = SKBuilders.kernel()
-        .setKernelConfig(config)
+        .withKernelConfig(config)
         .build();
 
     return kernel;

java/samples/sample-code/src/main/java/com/microsoft/semantickernel/syntaxexamples/Example02_Pipeline.java

@@ -11,7 +11,7 @@ import reactor.core.publisher.Mono;
 public class Example02_Pipeline {
     public static void main(String[] args) {
         KernelConfig kernelConfig = SKBuilders.kernelConfig().build();
-        Kernel kernel = SKBuilders.kernel().setKernelConfig(kernelConfig).build();
+        Kernel kernel = SKBuilders.kernel().withKernelConfig(kernelConfig).build();
 
         // Load native skill
         ReadOnlyFunctionCollection text = kernel.importSkill(new TextSkill(), null);

java/samples/sample-code/src/main/java/com/microsoft/semantickernel/syntaxexamples/Example03_Variables.java

@@ -37,7 +37,7 @@ public class Example03_Variables {
 
     public static void main(String[] args) {
         KernelConfig kernelConfig = SKBuilders.kernelConfig().build();
-        Kernel kernel = SKBuilders.kernel().setKernelConfig(kernelConfig).build();
+        Kernel kernel = SKBuilders.kernel().withKernelConfig(kernelConfig).build();
 
         // Load native skill
         ReadOnlyFunctionCollection functionCollection =

java/samples/sample-code/src/main/java/com/microsoft/semantickernel/syntaxexamples/Example04_CombineLLMPromptsAndNativeCode.java

@@ -36,7 +36,7 @@ public class Example04_CombineLLMPromptsAndNativeCode {
                 .addTextCompletionService("text-davinci-003", kernel -> textCompletion)
                 .build();
 
-        Kernel kernel = SKBuilders.kernel().setKernelConfig(kernelConfig).build();
+        Kernel kernel = SKBuilders.kernel().withKernelConfig(kernelConfig).build();
         kernel.importSkill(new SearchEngineSkill(), null);
         kernel.importSkillFromDirectory("SummarizeSkill", "./samples/skills", "SummarizeSkill");
 

java/samples/sample-code/src/main/java/com/microsoft/semantickernel/syntaxexamples/Example05_InlineFunctionDefinition.java

@@ -25,7 +25,7 @@ public class Example05_InlineFunctionDefinition {
                 .addTextCompletionService("text-davinci-003", kernel -> textCompletion)
                 .build();
 
-        Kernel kernel = SKBuilders.kernel().setKernelConfig(kernelConfig).build();
+        Kernel kernel = SKBuilders.kernel().withKernelConfig(kernelConfig).build();
 
         System.out.println("======== Inline Function Definition ========");
 

java/samples/sample-code/src/main/java/com/microsoft/semantickernel/syntaxexamples/Example06_TemplateLanguage.java

@@ -29,7 +29,7 @@ public class Example06_TemplateLanguage {
                 .build();
 
         Kernel kernel = SKBuilders.kernel()
-                .setKernelConfig(kernelConfig)
+                .withKernelConfig(kernelConfig)
                 .build();
 
         // Load native skill into the kernel skill collection, sharing its functions

java/samples/sample-code/src/main/java/com/microsoft/semantickernel/syntaxexamples/Example08_RetryHandler.java

@@ -77,7 +77,7 @@ public class Example08_RetryHandler {
 
         Kernel kernel = SKBuilders
                 .kernel()
-                .setKernelConfig(kernelConfig)
+                .withKernelConfig(kernelConfig)
                 .build();
 
         CompletionSKFunction summarizeFunc = SKBuilders.completionFunctions(kernel)
@@ -89,7 +89,6 @@ public class Example08_RetryHandler {
                         new PromptTemplateConfig.CompletionConfig(
                                 0.2, 0.5, 0, 0, 2000));
 
-
         kernel.registerSemanticFunction(summarizeFunc);
 
         SKContext context = summarizeFunc.invokeAsync(text).block();

java/samples/sample-code/src/main/java/com/microsoft/semantickernel/syntaxexamples/Example09_FunctionTypes.java

@@ -25,7 +25,7 @@ public class Example09_FunctionTypes {
                 .addTextCompletionService("text-davinci-003", kernel -> textCompletion)
                 .build();
 
-        Kernel kernel = SKBuilders.kernel().setKernelConfig(kernelConfig).build();
+        Kernel kernel = SKBuilders.kernel().withKernelConfig(kernelConfig).build();
 
         System.out.println("======== Native function types ========");
 

java/samples/sample-code/src/main/java/com/microsoft/semantickernel/syntaxexamples/Example12_SequentialPlanner.java

@@ -175,7 +175,7 @@ public class Example12_SequentialPlanner {
     private static Kernel initializeKernel() throws IOException {
         OpenAIAsyncClient client = Config.getClient();
         var kernel = SKBuilders.kernel()
-                .setKernelConfig(SKBuilders
+                .withKernelConfig(SKBuilders
                         .kernelConfig()
                         .addTextCompletionService("text-davinci-003", kernel1 -> SKBuilders.textCompletionService()
                                 .build(client, "text-davinci-003"))

java/samples/sample-code/src/main/java/com/microsoft/semantickernel/syntaxexamples/Example13_ConversationSummarySkill.java

@@ -186,9 +186,10 @@ public class Example13_ConversationSummarySkill {
 
         KernelConfig kernelConfig =
                 new KernelConfig.Builder()
-                        .addTextCompletionService("text-davinci-003", kernel -> textCompletion)
                         .build();
 
-        return SKBuilders.kernel().setKernelConfig(kernelConfig).build();
+        return SKBuilders.kernel()
+                .withKernelConfig(kernelConfig)
+                .withAIService("text-davinci-003", textCompletion, true, TextCompletion.class).build();
     }
 }

java/samples/sample-code/src/main/java/com/microsoft/semantickernel/syntaxexamples/Example14_SemanticMemory.java

@@ -5,7 +5,6 @@ import com.microsoft.semantickernel.Config;
 import com.microsoft.semantickernel.Kernel;
 import com.microsoft.semantickernel.builders.SKBuilders;
 import com.microsoft.semantickernel.connectors.memory.azurecognitivesearch.AzureCognitiveSearchMemory;
-import com.microsoft.semantickernel.memory.SemanticTextMemory;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 
@@ -42,7 +41,7 @@ public class Example14_SemanticMemory
         var kernelConfig = SKBuilders.kernelConfig().build();
 
         var kernelWithACS = SKBuilders.kernel()
-                .setKernelConfig(kernelConfig)
+                .withKernelConfig(kernelConfig)
                 .withMemory(new AzureCognitiveSearchMemory(System.getenv("ACS_ENDPOINT"), System.getenv("ACS_API_KEY")))
                 .build();
 
@@ -69,7 +68,7 @@ public class Example14_SemanticMemory
                 .build();
 
         var kernelWithCustomDb = SKBuilders.kernel()
-                .setKernelConfig(kernelConfigWithTextEmbedding)
+                .withKernelConfig(kernelConfigWithTextEmbedding)
                 .withMemoryStore(SKBuilders.memoryStore().build())
                 .build();
 

java/samples/sample-code/src/main/java/com/microsoft/semantickernel/syntaxexamples/Example17_ChatGPT.java

@@ -4,7 +4,6 @@ package com.microsoft.semantickernel.syntaxexamples;
 import com.azure.ai.openai.OpenAIAsyncClient;
 import com.microsoft.semantickernel.Config;
 import com.microsoft.semantickernel.Kernel;
-import com.microsoft.semantickernel.KernelConfig;
 import com.microsoft.semantickernel.builders.SKBuilders;
 import com.microsoft.semantickernel.chatcompletion.ChatCompletion;
 import com.microsoft.semantickernel.chatcompletion.ChatHistory;
@@ -21,14 +20,17 @@ public class Example17_ChatGPT {
     public static void main(String[] args) throws IOException {
         OpenAIAsyncClient client = Config.ClientType.AZURE_OPEN_AI.getClient();
 
-        KernelConfig kernelConfig = SKBuilders.kernelConfig()
-                .addChatCompletionService(
+        Kernel kernel = SKBuilders.kernel()
+                .withKernelConfig(SKBuilders.kernelConfig()
+                        .build())
+                .withAIService(
                         "chat-test",
-                        kernel -> SKBuilders.chatCompletion().build(client, "chat-test"))
+                        SKBuilders.chatCompletion().build(client, "chat-test"),
+                        true,
+                        ChatCompletion.class
+                )
                 .build();
 
-        Kernel kernel = SKBuilders.kernel().setKernelConfig(kernelConfig).build();
-
         ChatCompletion<OpenAIChatHistory> chatGPT = kernel.getService(null, ChatCompletion.class);
 
         OpenAIChatHistory chatHistory = chatGPT.createNewChat("You are a librarian, expert about books");

java/samples/sample-code/src/main/java/com/microsoft/semantickernel/syntaxexamples/Example28_ActionPlanner.java

@@ -16,7 +16,7 @@ public class Example28_ActionPlanner {
         System.out.println("======== Action Planner ========");
 
         var kernel = SKBuilders.kernel()
-                .setKernelConfig(SKBuilders
+                .withKernelConfig(SKBuilders
                         .kernelConfig()
                         .addTextCompletionService("text-davinci-002", kernel1 -> SKBuilders.textCompletionService()
                                 .build(client, "text-davinci-002"))

java/semantickernel-api/src/main/java/com/microsoft/semantickernel/Kernel.java

@@ -7,11 +7,17 @@ import com.microsoft.semantickernel.memory.SemanticTextMemory;
 import com.microsoft.semantickernel.orchestration.ContextVariables;
 import com.microsoft.semantickernel.orchestration.SKContext;
 import com.microsoft.semantickernel.orchestration.SKFunction;
+import com.microsoft.semantickernel.services.AIService;
+import com.microsoft.semantickernel.services.AIServiceCollection;
+import com.microsoft.semantickernel.services.AIServiceProvider;
 import com.microsoft.semantickernel.templateengine.PromptTemplateEngine;
 import com.microsoft.semantickernel.textcompletion.CompletionSKFunction;
 
 import reactor.core.publisher.Mono;
 
+import java.util.function.Function;
+import java.util.function.Supplier;
+
 import javax.annotation.Nullable;
 
 /** Interface for the semantic kernel. */
@@ -66,7 +72,8 @@ public interface Kernel extends SkillExecutor {
     CompletionSKFunction.Builder getSemanticFunctionBuilder();
 
     /** Obtains the service with the given name and type */
-    <T> T getService(@Nullable String name, Class<T> clazz) throws KernelException;
+    <T extends AIService> T getService(@Nullable String name, Class<T> clazz)
+            throws KernelException;
 
     /** Registers a semantic functon on this kernel */
     <RequestConfiguration, FunctionType extends SKFunction<RequestConfiguration>>
@@ -80,14 +87,15 @@ public interface Kernel extends SkillExecutor {
         @Nullable private KernelConfig kernelConfig = null;
         @Nullable private PromptTemplateEngine promptTemplateEngine = null;
         @Nullable private MemoryStore memoryStore = null;
+        @Nullable private AIServiceCollection aiServices = new AIServiceCollection();
         @Nullable private SemanticTextMemory memory = null;
 
-        public Builder setKernelConfig(KernelConfig kernelConfig) {
+        public Builder withKernelConfig(KernelConfig kernelConfig) {
             this.kernelConfig = kernelConfig;
             return this;
         }
 
-        public Builder setPromptTemplateEngine(PromptTemplateEngine promptTemplateEngine) {
+        public Builder withPromptTemplateEngine(PromptTemplateEngine promptTemplateEngine) {
             this.promptTemplateEngine = promptTemplateEngine;
             return this;
         }
@@ -97,6 +105,65 @@ public interface Kernel extends SkillExecutor {
             return this;
         }
 
+        /**
+         * Adds an instance to the services collection
+         *
+         * @param instance The instance.
+         * @param clazz The class of the instance.
+         * @return The builder.
+         */
+        public <T extends AIService> Builder withDefaultAIService(T instance, Class<T> clazz) {
+            this.aiServices.setService(instance, clazz);
+            return this;
+        }
+
+        /**
+         * Adds an instance to the services collection
+         *
+         * @param serviceId The service ID
+         * @param instance The instance.
+         * @param setAsDefault Optional: set as the default AI service for type T
+         * @param clazz The class of the instance.
+         */
+        public <T extends AIService> Builder withAIService(
+                @Nullable String serviceId, T instance, boolean setAsDefault, Class<T> clazz) {
+            this.aiServices.setService(serviceId, instance, setAsDefault, clazz);
+            return this;
+        }
+
+        /**
+         * Adds a factory method to the services collection
+         *
+         * @param factory The factory method that creates the AI service instances of type T.
+         * @param clazz The class of the instance.
+         */
+        public <T extends AIService> Builder withDefaultAIService(
+                Supplier<T> factory, Class<T> clazz) {
+            this.aiServices.setService(factory, clazz);
+            return this;
+        }
+
+        /**
+         * Adds a factory method to the services collection
+         *
+         * @param serviceId The service ID
+         * @param factory The factory method that creates the AI service instances of type T.
+         * @param setAsDefault Optional: set as the default AI service for type T
+         * @param clazz The class of the instance.
+         */
+        public <T extends AIService> Builder withAIService(
+                @Nullable String serviceId,
+                Function<KernelConfig, T> factory,
+                boolean setAsDefault,
+                Class<T> clazz) {
+            this.aiServices.setService(
+                    serviceId,
+                    (Supplier<T>) () -> factory.apply(this.kernelConfig),
+                    setAsDefault,
+                    clazz);
+            return this;
+        }
+
         public Builder withMemory(SemanticTextMemory memory) {
             this.memory = memory;
             return this;
@@ -109,7 +176,12 @@ public interface Kernel extends SkillExecutor {
 
             return BuildersSingleton.INST
                     .getKernelBuilder()
-                    .build(kernelConfig, promptTemplateEngine, memory, memoryStore);
+                    .build(
+                            kernelConfig,
+                            promptTemplateEngine,
+                            memory,
+                            memoryStore,
+                            aiServices.build());
         }
     }
 
@@ -118,6 +190,7 @@ public interface Kernel extends SkillExecutor {
                 KernelConfig kernelConfig,
                 @Nullable PromptTemplateEngine promptTemplateEngine,
                 @Nullable SemanticTextMemory memory,
-                @Nullable MemoryStore memoryStore);
+                @Nullable MemoryStore memoryStore,
+                @Nullable AIServiceProvider aiServiceProvider);
     }
 }

java/semantickernel-api/src/main/java/com/microsoft/semantickernel/ai/embeddings/EmbeddingGeneration.java

@@ -2,13 +2,14 @@
 package com.microsoft.semantickernel.ai.embeddings;
 
 import com.azure.ai.openai.OpenAIAsyncClient;
+import com.microsoft.semantickernel.services.AIService;
 
 import reactor.core.publisher.Mono;
 
 import java.util.List;
 
 /** Interface for text embedding generation services */
-public interface EmbeddingGeneration<TValue, TEmbedding extends Number> {
+public interface EmbeddingGeneration<TValue, TEmbedding extends Number> extends AIService {
     /**
      * Generates a list of embeddings associated to the data
      *

java/semantickernel-api/src/main/java/com/microsoft/semantickernel/chatcompletion/ChatCompletion.java

@@ -2,12 +2,13 @@
 package com.microsoft.semantickernel.chatcompletion;
 
 import com.azure.ai.openai.OpenAIAsyncClient;
+import com.microsoft.semantickernel.services.AIService;
 
 import reactor.core.publisher.Mono;
 
 import javax.annotation.Nullable;
 
-public interface ChatCompletion<ChatHistoryType extends ChatHistory> {
+public interface ChatCompletion<ChatHistoryType extends ChatHistory> extends AIService {
     /**
      * Generate a new chat message
      *

java/semantickernel-api/src/main/java/com/microsoft/semantickernel/services/AIService.java

@@ -0,0 +1,5 @@
+// Copyright (c) Microsoft. All rights reserved.
+package com.microsoft.semantickernel.services;
+
+/** Marker interface for AI services */
+public interface AIService {}

java/semantickernel-api/src/main/java/com/microsoft/semantickernel/services/AIServiceCollection.java

@@ -0,0 +1,138 @@
+// Copyright (c) Microsoft. All rights reserved.
+package com.microsoft.semantickernel.services;
+
+import com.microsoft.semantickernel.Verify;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Supplier;
+
+import javax.annotation.Nullable;
+
+/** A collection that can hold AI services */
+public class AIServiceCollection {
+    // A constant key for the default service
+    private static final String DefaultKey = "__DEFAULT__";
+
+    // A dictionary that maps a service type to a nested dictionary of names and service instances
+    // or factories
+    // private readonly Dictionary<Type, Dictionary<string, object>> _services = new();
+    private final Map<Class<? extends AIService>, Map<String, Supplier<? extends AIService>>>
+            services = new HashMap<>();
+
+    // A dictionary that maps a service type to the name of the default service
+    private final Map<Class<? extends AIService>, String> defaultIds = new HashMap<>();
+
+    /**
+     * Registers a singleton service instance with the default name.
+     *
+     * @param service The service instance.
+     * @param serviceType The type of the service.
+     */
+    public <T extends AIService> void setService(T service, Class<T> serviceType) {
+        setService(DefaultKey, (Supplier<T>) () -> service, true, serviceType);
+    }
+
+    /**
+     * Registers a singleton service instance with an optional name and default flag.
+     *
+     * @param name The name of the service, or null for the default service.
+     * @param service The service instance.
+     * @param setAsDefault Whether the service should be the default for its type.
+     * @param serviceType The type of the service.
+     */
+    public <T extends AIService> void setService(
+            String name, T service, boolean setAsDefault, Class<T> serviceType) {
+        setService(name, (Supplier<T>) () -> service, setAsDefault, serviceType);
+    }
+
+    /**
+     * Registers a transient service factory with the default name.
+     *
+     * @param factory The factory function to create the service instance.
+     * @param serviceType The type of the service.
+     */
+    public <T extends AIService> void setService(Supplier<T> factory, Class<T> serviceType) {
+        setService(DefaultKey, factory, true, serviceType);
+    }
+
+    /**
+     * Registers a transient service factory with an optional name and default flag.
+     *
+     * @param name The name of the service, or null for the default service.
+     * @param factory The factory function to create the service instance.
+     * @param setAsDefault Whether the service should be the default for its type.
+     * @param serviceType The type of the service.
+     */
+    public <T extends AIService> void setService(
+            @Nullable String name,
+            Supplier<T> factory,
+            boolean setAsDefault,
+            Class<T> serviceType) {
+        // Validate the factory function
+        if (factory == null) {
+            throw new IllegalArgumentException();
+        }
+
+        // Get or create the nested dictionary for the service type
+        Map<String, Supplier<? extends AIService>> namedServices = this.services.get(serviceType);
+        if (namedServices == null) {
+            namedServices = new HashMap<>();
+            services.put(serviceType, namedServices);
+        }
+
+        // Set as the default if the name is empty, or the default flag is true,
+        // or there is no default name for the service type.
+        if (name == null || setAsDefault || !this.hasDefault(serviceType)) {
+            // Update the default name for the service type
+            this.defaultIds.put(serviceType, name == null ? DefaultKey : name);
+        }
+
+        // Register the factory with the given name
+        namedServices.put(name == null ? DefaultKey : name, factory);
+    }
+
+    /**
+     * Builds an AIServiceProvider from the registered services and default names.
+     *
+     * @return The AIServiceProvider.
+     */
+    public AIServiceProvider build() {
+        // Create a clone of the services and defaults Dictionaries to prevent further changes
+        // by the services provider.
+        Map<Class<? extends AIService>, Map<String, Supplier<? extends AIService>>> servicesClone =
+                cloneServices(services);
+
+        Map defaultsClone = new HashMap<>(defaultIds);
+
+        return new DefaultAIServiceProvider(servicesClone, defaultsClone);
+    }
+
+    /**
+     * Creates a clone of the services as a Map.
+     *
+     * @param services The services Map.
+     * @return The clone.
+     */
+    static <T> Map<Class<? extends T>, Map<String, Supplier<? extends T>>> cloneServices(
+            Map<Class<? extends T>, Map<String, Supplier<? extends T>>> services) {
+        return Collections.unmodifiableMap(
+                services.entrySet().stream()
+                        .reduce(
+                                new HashMap<>(),
+                                (a, b) -> {
+                                    a.put(b.getKey(), Collections.unmodifiableMap(b.getValue()));
+                                    return a;
+                                },
+                                (a, b) -> {
+                                    a.putAll(b);
+                                    return a;
+                                }));
+    }
+
+    private <T extends AIService> boolean hasDefault(Class<T> type) {
+        String defaultName = defaultIds.get(type);
+        return !Verify.isNullOrEmpty(defaultName);
+    }
+}

java/semantickernel-api/src/main/java/com/microsoft/semantickernel/services/AIServiceProvider.java

@@ -0,0 +1,4 @@
+// Copyright (c) Microsoft. All rights reserved.
+package com.microsoft.semantickernel.services;
+
+public interface AIServiceProvider extends NamedServiceProvider<AIService> {}

java/semantickernel-api/src/main/java/com/microsoft/semantickernel/services/DefaultAIServiceProvider.java

@@ -0,0 +1,15 @@
+// Copyright (c) Microsoft. All rights reserved.
+package com.microsoft.semantickernel.services;
+
+import java.util.Map;
+import java.util.function.Supplier;
+
+/** Default implementation of {@link AIServiceProvider} */
+public class DefaultAIServiceProvider extends DefaultNamedServiceProvider<AIService>
+        implements AIServiceProvider {
+    public DefaultAIServiceProvider(
+            Map<Class<? extends AIService>, Map<String, Supplier<? extends AIService>>> services,
+            Map<Class<? extends AIService>, String> defaultIds) {
+        super(services, defaultIds);
+    }
+}

java/semantickernel-api/src/main/java/com/microsoft/semantickernel/services/DefaultNamedServiceProvider.java

@@ -0,0 +1,86 @@
+// Copyright (c) Microsoft. All rights reserved.
+package com.microsoft.semantickernel.services;
+
+import com.microsoft.semantickernel.Verify;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.Supplier;
+
+import javax.annotation.Nullable;
+
+/** Default implementation of {@link NamedServiceProvider} */
+public class DefaultNamedServiceProvider<T> implements NamedServiceProvider<T> {
+
+    // A dictionary that maps a service type to a nested dictionary of names and service instances
+    // or factories
+    // private readonly Dictionary<Type, Dictionary<string, object>> _services = new();
+    private final Map<Class<? extends T>, Map<String, Supplier<? extends T>>> services;
+
+    // A dictionary that maps a service type to the name of the default service
+    private final Map<Class<? extends T>, String> defaultIds;
+
+    public DefaultNamedServiceProvider(
+            Map<Class<? extends T>, Map<String, Supplier<? extends T>>> services,
+            Map<Class<? extends T>, String> defaultIds) {
+        this.services = AIServiceCollection.cloneServices(services);
+        this.defaultIds = new HashMap<>(defaultIds);
+    }
+
+    /**
+     * Gets the service of the specified type and name, or null if not found.
+     *
+     * @param name The name of the service, or null for the default service.
+     * @param clazz The type of the service.
+     * @return The service instance, or null if not found.
+     */
+    @Nullable
+    @Override
+    public <U extends T> U getService(@Nullable String name, Class<U> clazz) {
+        // Return the service, casting or invoking the factory if needed
+        Supplier<U> factory = this.getServiceFactory(name, clazz);
+        if (factory != null) {
+            return factory.get();
+        }
+
+        return null;
+    }
+
+    /**
+     * Get the default service instance.
+     *
+     * @param clazz The type of the service.
+     * @return The service instance, or null if none.
+     */
+    @Nullable
+    private <U extends T> String getDefaultServiceName(Class<U> clazz) {
+        // Returns the name of the default service for the given type, or null if none
+        String name = this.defaultIds.get(clazz);
+        if (!Verify.isNullOrEmpty(name)) {
+            return name;
+        }
+
+        return null;
+    }
+
+    @Nullable
+    private <U extends T> Supplier<U> getServiceFactory(@Nullable String name, Class<U> clazz) {
+        // Get the nested dictionary for the service type
+        Map<String, Supplier<? extends T>> namedServices = services.get(clazz);
+
+        if (namedServices != null) {
+            Supplier<U> serviceFactory = null;
+
+            // If the name is not specified, try to load the default factory
+            name = name == null ? this.getDefaultServiceName(clazz) : name;
+            if (name != null) {
+                // Check if there is a service registered with the given name
+                serviceFactory = (Supplier<U>) namedServices.get(name);
+            }
+
+            return serviceFactory;
+        }
+
+        return null;
+    }
+}

java/semantickernel-api/src/main/java/com/microsoft/semantickernel/services/NamedServiceProvider.java

@@ -0,0 +1,16 @@
+// Copyright (c) Microsoft. All rights reserved.
+package com.microsoft.semantickernel.services;
+
+import javax.annotation.Nullable;
+
+public interface NamedServiceProvider<T> {
+    /**
+     * Gets the service of the specified type and name, or null if not found.
+     *
+     * @param name The name of the service, or null for the default service.
+     * @param clazz The type of the service.
+     * @return The service instance, or null if not found.
+     */
+    @Nullable
+    public <U extends T> U getService(@Nullable String name, Class<U> clazz);
+}

java/semantickernel-api/src/main/java/com/microsoft/semantickernel/textcompletion/TextCompletion.java

@@ -2,13 +2,14 @@
 package com.microsoft.semantickernel.textcompletion;
 
 import com.azure.ai.openai.OpenAIAsyncClient;
+import com.microsoft.semantickernel.services.AIService;
 
 import reactor.core.publisher.Mono;
 
 import java.util.List;
 
 /** Interface for text completion services */
-public interface TextCompletion {
+public interface TextCompletion extends AIService {
     // TODO: Support Cancellation Token
 
     /**

java/semantickernel-core/src/main/java/com/microsoft/semantickernel/DefaultKernel.java

@@ -7,7 +7,6 @@ import com.microsoft.semantickernel.builders.FunctionBuilders;
 import com.microsoft.semantickernel.builders.SKBuilders;
 import com.microsoft.semantickernel.chatcompletion.ChatCompletion;
 import com.microsoft.semantickernel.coreskills.SkillImporter;
-import com.microsoft.semantickernel.exceptions.NotSupportedException;
 import com.microsoft.semantickernel.exceptions.SkillsNotFoundException;
 import com.microsoft.semantickernel.extensions.KernelExtensions;
 import com.microsoft.semantickernel.memory.MemoryConfiguration;
@@ -16,6 +15,8 @@ import com.microsoft.semantickernel.memory.NullMemory;
 import com.microsoft.semantickernel.memory.SemanticTextMemory;
 import com.microsoft.semantickernel.orchestration.*;
 import com.microsoft.semantickernel.semanticfunctions.SemanticFunctionConfig;
+import com.microsoft.semantickernel.services.AIService;
+import com.microsoft.semantickernel.services.AIServiceProvider;
 import com.microsoft.semantickernel.skilldefinition.DefaultSkillCollection;
 import com.microsoft.semantickernel.skilldefinition.FunctionNotFound;
 import com.microsoft.semantickernel.skilldefinition.ReadOnlyFunctionCollection;
@@ -41,18 +42,21 @@ public class DefaultKernel implements Kernel {
     private final KernelConfig kernelConfig;
     private final DefaultSkillCollection defaultSkillCollection;
     private final PromptTemplateEngine promptTemplateEngine;
+    private final AIServiceProvider aiServiceProvider;
     private SemanticTextMemory memory;
 
     @Inject
     public DefaultKernel(
             KernelConfig kernelConfig,
             PromptTemplateEngine promptTemplateEngine,
-            @Nullable SemanticTextMemory memoryStore) {
+            @Nullable SemanticTextMemory memoryStore,
+            AIServiceProvider aiServiceProvider) {
         if (kernelConfig == null) {
             throw new IllegalArgumentException();
         }
 
         this.kernelConfig = kernelConfig;
+        this.aiServiceProvider = aiServiceProvider;
         this.promptTemplateEngine = promptTemplateEngine;
         this.defaultSkillCollection = new DefaultSkillCollection();
 
@@ -64,7 +68,14 @@ public class DefaultKernel implements Kernel {
     }
 
     @Override
-    public <T> T getService(@Nullable String serviceId, Class<T> clazz) {
+    public <T extends AIService> T getService(String serviceId, Class<T> clazz) {
+
+        T service = aiServiceProvider.getService(serviceId, clazz);
+
+        if (service != null) {
+            return service;
+        }
+
         if (TextCompletion.class.isAssignableFrom(clazz)) {
             Function<Kernel, TextCompletion> factory =
                     kernelConfig.getTextCompletionServiceOrDefault(serviceId);
@@ -94,11 +105,25 @@ public class DefaultKernel implements Kernel {
                         "No chat completion service available");
             }
 
+            return (T) factory.apply(this);
+        } else if (EmbeddingGeneration.class.isAssignableFrom(clazz)) {
+            Function<Kernel, EmbeddingGeneration<String, Float>> factory =
+                    kernelConfig.getTextEmbeddingGenerationServiceOrDefault(serviceId);
+            if (factory == null) {
+                throw new KernelException(
+                        KernelException.ErrorCodes.ServiceNotFound,
+                        "No chat completion service available");
+            }
+
             return (T) factory.apply(this);
         } else {
-            // TODO correct exception
-            throw new NotSupportedException(
-                    "The kernel service collection doesn't support the type " + clazz.getName());
+            throw new KernelException(
+                    KernelException.ErrorCodes.ServiceNotFound,
+                    "Service of type "
+                            + clazz.getName()
+                            + " and name "
+                            + serviceId
+                            + " not registered");
         }
     }
 
@@ -311,7 +336,8 @@ public class DefaultKernel implements Kernel {
                 KernelConfig kernelConfig,
                 @Nullable PromptTemplateEngine promptTemplateEngine,
                 @Nullable SemanticTextMemory memory,
-                @Nullable MemoryStore memoryStore) {
+                @Nullable MemoryStore memoryStore,
+                @Nullable AIServiceProvider aiServiceProvider) {
             if (promptTemplateEngine == null) {
                 promptTemplateEngine = new DefaultPromptTemplateEngine();
             }
@@ -322,7 +348,9 @@ public class DefaultKernel implements Kernel {
                         "It is required to set a kernelConfig to build a kernel");
             }
 
-            DefaultKernel kernel = new DefaultKernel(kernelConfig, promptTemplateEngine, memory);
+            DefaultKernel kernel =
+                    new DefaultKernel(
+                            kernelConfig, promptTemplateEngine, memory, aiServiceProvider);
 
             if (memoryStore != null) {
                 MemoryConfiguration.useMemory(kernel, memoryStore, null);

java/semantickernel-core/src/main/java/com/microsoft/semantickernel/skilldefinition/DefaultSkillCollection.java

@@ -124,7 +124,7 @@ public class DefaultSkillCollection implements ReadOnlySkillCollection {
         return addSemanticFunction(functionInstance);
     }
 
-    public DefaultSkillCollection merge(DefaultSkillCollection in) {
+    public DefaultSkillCollection merge(ReadOnlySkillCollection in) {
         in.asMap()
                 .entrySet()
                 .forEach(

java/semantickernel-core/src/test/java/com/microsoft/semantickernel/AiServiceRegistryTest.java

@@ -0,0 +1,70 @@
+// Copyright (c) Microsoft. All rights reserved.
+package com.microsoft.semantickernel;
+
+import com.microsoft.semantickernel.builders.SKBuilders;
+import com.microsoft.semantickernel.textcompletion.CompletionSKFunction;
+import com.microsoft.semantickernel.textcompletion.TextCompletion;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+import org.mockito.Mockito;
+
+import reactor.core.publisher.Mono;
+
+import java.util.Collections;
+
+public class AiServiceRegistryTest {
+
+    @Test
+    public void registeredServicesAreAvailableInTheKernel() {
+        runFunctionWithAiService(true);
+    }
+
+    @Test
+    public void singleServiceIsRegisteredAsDefault() {
+        runFunctionWithAiService(false);
+    }
+
+    private static void runFunctionWithAiService(boolean setAsDefault) {
+        KernelConfig config = SKBuilders.kernelConfig().build();
+        TextCompletion service = Mockito.mock(TextCompletion.class);
+        Mockito.when(service.completeAsync(Mockito.any(), Mockito.any()))
+                .thenReturn(Mono.just(Collections.singletonList("foo")));
+
+        Kernel kernel =
+                SKBuilders.kernel()
+                        .withAIService("a-service", service, setAsDefault, TextCompletion.class)
+                        .withKernelConfig(config)
+                        .build();
+
+        Assertions.assertSame(kernel.getService("a-service", TextCompletion.class), service);
+
+        CompletionSKFunction function =
+                kernel.importSkillFromDirectory("FunSkill", "../../samples/skills")
+                        .getFunction("joke", CompletionSKFunction.class);
+
+        function.invokeAsync("time travel to dinosaur age").block();
+
+        Mockito.verify(service, Mockito.times(1)).completeAsync(Mockito.any(), Mockito.any());
+    }
+
+    @Test
+    public void noServiceThrowsAnError() {
+        KernelConfig config = SKBuilders.kernelConfig().build();
+
+        Kernel kernel = SKBuilders.kernel().withKernelConfig(config).build();
+
+        Assertions.assertThrows(
+                KernelException.class, () -> kernel.getService("a-service", TextCompletion.class));
+
+        Assertions.assertThrows(
+                KernelException.class,
+                () -> {
+                    CompletionSKFunction function =
+                            kernel.importSkillFromDirectory("FunSkill", "../../samples/skills")
+                                    .getFunction("joke", CompletionSKFunction.class);
+
+                    function.invokeAsync("time travel to dinosaur age").block();
+                });
+    }
+}

java/semantickernel-core/src/test/java/com/microsoft/semantickernel/DefaultKernelTest.java

@@ -119,7 +119,7 @@ public class DefaultKernelTest {
                         .addTextCompletionService(model, kernel -> textCompletion)
                         .build();
 
-        return SKBuilders.kernel().setKernelConfig(kernelConfig).build();
+        return SKBuilders.kernel().withKernelConfig(kernelConfig).build();
     }
 
     private static OpenAIAsyncClient mockCompletionOpenAIAsyncClient(String arg, String response) {

java/semantickernel-core/src/test/java/com/microsoft/semantickernel/connectors/ai/openai/chatcompletion/OpenAIChatCompletionTest.java

@@ -46,7 +46,7 @@ public class OpenAIChatCompletionTest {
                                                 .build(client, "gpt-3.5-turbo-0301"))
                         .build();
 
-        Kernel kernel = SKBuilders.kernel().setKernelConfig(kernelConfig).build();
+        Kernel kernel = SKBuilders.kernel().withKernelConfig(kernelConfig).build();
 
         ChatCompletion<OpenAIChatHistory> chatGPT = kernel.getService(null, ChatCompletion.class);
 

java/semantickernel-core/src/test/java/com/microsoft/semantickernel/connectors/memory/azurecognitivesearch/AzureCognitiveSearchMemoryTests.java

@@ -99,7 +99,7 @@ class AzureCognitiveSearchMemoryTests {
 
         kernel =
                 SKBuilders.kernel()
-                        .setKernelConfig(SKBuilders.kernelConfig().build())
+                        .withKernelConfig(SKBuilders.kernelConfig().build())
                         .withMemory(new AzureCognitiveSearchMemory(searchIndexAsyncClient))
                         .build();
     }

java/semantickernel-core/src/test/java/com/microsoft/semantickernel/syntaxexamples/Example04CombineLLMPromptsAndNativeCodeTest.java

@@ -38,7 +38,7 @@ public class Example04CombineLLMPromptsAndNativeCodeTest {
                         .setDefaultTextCompletionService("text-davinci-003")
                         .build();
 
-        Kernel kernel = SKBuilders.kernel().setKernelConfig(kernelConfig).build();
+        Kernel kernel = SKBuilders.kernel().withKernelConfig(kernelConfig).build();
         kernel.importSkill(new SearchEngineSkill(), null);
         kernel.importSkillFromDirectory("SummarizeSkill", "../../samples/skills", "SummarizeSkill");
 

java/semantickernel-core/src/test/java/com/microsoft/semantickernel/syntaxexamples/Example05UsingThePlannerTest.java

@@ -43,7 +43,7 @@ public class Example05UsingThePlannerTest {
                                                 .build(client, "text-davinci-003"))
                         .build();
 
-        Kernel kernel = SKBuilders.kernel().setKernelConfig(config).build();
+        Kernel kernel = SKBuilders.kernel().withKernelConfig(config).build();
 
         SequentialPlanner planner = getPlanner(kernel);
         System.out.println(

java/semantickernel-core/src/test/java/com/microsoft/semantickernel/syntaxexamples/Example06TemplateLanguageTest.java

@@ -35,7 +35,7 @@ public class Example06TemplateLanguageTest {
                                                 .build(client, "text-davinci-003"))
                         .build();
 
-        Kernel kernel = SKBuilders.kernel().setKernelConfig(kernelConfig).build();
+        Kernel kernel = SKBuilders.kernel().withKernelConfig(kernelConfig).build();
 
         // Load native skill into the kernel skill collection, sharing its functions
         // with prompt

java/semantickernel-core/src/test/java/com/microsoft/semantickernel/syntaxexamples/Example12SequentialPlannerTest.java

@@ -80,7 +80,7 @@ public class Example12SequentialPlannerTest {
     private static Kernel getKernel(OpenAIAsyncClient client) {
         Kernel kernel =
                 SKBuilders.kernel()
-                        .setKernelConfig(
+                        .withKernelConfig(
                                 SKBuilders.kernelConfig()
                                         .addTextCompletionService(
                                                 "text-davinci-002",

java/semantickernel-core/src/test/java/com/microsoft/semantickernel/syntaxexamples/Example17ChatGPTTest.java

@@ -48,7 +48,7 @@ public class Example17ChatGPTTest {
                                                 .build(client, "gpt-3.5-turbo-0301"))
                         .build();
 
-        Kernel kernel = SKBuilders.kernel().setKernelConfig(kernelConfig).build();
+        Kernel kernel = SKBuilders.kernel().withKernelConfig(kernelConfig).build();
 
         ChatCompletion<OpenAIChatHistory> chatGPT = kernel.getService(null, ChatCompletion.class);
 

java/semantickernel-core/src/test/java/com/microsoft/semantickernel/syntaxexamples/Example28ActionPlanner.java

@@ -123,7 +123,7 @@ public class Example28ActionPlanner {
     private static ActionPlanner createPlanner(OpenAIAsyncClient client) {
         Kernel kernel =
                 SKBuilders.kernel()
-                        .setKernelConfig(
+                        .withKernelConfig(
                                 SKBuilders.kernelConfig()
                                         .addTextCompletionService(
                                                 "text-davinci-002",