diff --git a/advisors/spring-ai-advisors-vector-store/src/main/java/org/springframework/ai/chat/client/advisor/vectorstore/VectorStoreChatMemoryAdvisor.java b/advisors/spring-ai-advisors-vector-store/src/main/java/org/springframework/ai/chat/client/advisor/vectorstore/VectorStoreChatMemoryAdvisor.java
index 33e4ae2ba2e..398710b55c6 100644
--- a/advisors/spring-ai-advisors-vector-store/src/main/java/org/springframework/ai/chat/client/advisor/vectorstore/VectorStoreChatMemoryAdvisor.java
+++ b/advisors/spring-ai-advisors-vector-store/src/main/java/org/springframework/ai/chat/client/advisor/vectorstore/VectorStoreChatMemoryAdvisor.java
@@ -209,7 +209,7 @@ else if (message instanceof AssistantMessage assistantMessage) {
 	/**
 	 * Builder for VectorStoreChatMemoryAdvisor.
 	 */
-	public static class Builder {
+	public static final class Builder {
 
 		private PromptTemplate systemPromptTemplate = DEFAULT_SYSTEM_PROMPT_TEMPLATE;
 
diff --git a/mcp/common/src/main/java/org/springframework/ai/mcp/AsyncMcpToolCallback.java b/mcp/common/src/main/java/org/springframework/ai/mcp/AsyncMcpToolCallback.java
index 3effabcbe18..9e1b46b4c41 100644
--- a/mcp/common/src/main/java/org/springframework/ai/mcp/AsyncMcpToolCallback.java
+++ b/mcp/common/src/main/java/org/springframework/ai/mcp/AsyncMcpToolCallback.java
@@ -160,7 +160,7 @@ public static Builder builder() {
 	/**
 	 * Builder for constructing AsyncMcpToolCallback instances.
 	 */
-	public static class Builder {
+	public static final class Builder {
 
 		private McpAsyncClient mcpClient;
 
diff --git a/mcp/common/src/main/java/org/springframework/ai/mcp/SyncMcpToolCallback.java b/mcp/common/src/main/java/org/springframework/ai/mcp/SyncMcpToolCallback.java
index 74591adf253..277401594c2 100644
--- a/mcp/common/src/main/java/org/springframework/ai/mcp/SyncMcpToolCallback.java
+++ b/mcp/common/src/main/java/org/springframework/ai/mcp/SyncMcpToolCallback.java
@@ -160,7 +160,7 @@ public static Builder builder() {
 	/**
 	 * Builder for {@code SyncMcpToolCallback} instances.
 	 */
-	public static class Builder {
+	public static final class Builder {
 
 		private McpSyncClient mcpClient;
 
diff --git a/mcp/common/src/main/java/org/springframework/ai/mcp/SyncMcpToolCallbackProvider.java b/mcp/common/src/main/java/org/springframework/ai/mcp/SyncMcpToolCallbackProvider.java
index 2e1a6e5ee52..298f07596be 100644
--- a/mcp/common/src/main/java/org/springframework/ai/mcp/SyncMcpToolCallbackProvider.java
+++ b/mcp/common/src/main/java/org/springframework/ai/mcp/SyncMcpToolCallbackProvider.java
@@ -179,7 +179,7 @@ public static Builder builder() {
 	/**
 	 * Builder for {@code SyncMcpToolCallbackProvider}.
 	 */
-	public static class Builder {
+	public static final class Builder {
 
 		private List<McpSyncClient> mcpClients = new ArrayList<>();
 
diff --git a/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/AnthropicChatOptions.java b/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/AnthropicChatOptions.java
index dcf0d9bc55b..959a971bf85 100644
--- a/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/AnthropicChatOptions.java
+++ b/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/AnthropicChatOptions.java
@@ -307,7 +307,7 @@ public int hashCode() {
 				this.toolContext, this.httpHeaders, this.cacheOptions);
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private final AnthropicChatOptions options = new AnthropicChatOptions();
 
diff --git a/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/api/AnthropicApi.java b/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/api/AnthropicApi.java
index eae45fb6e78..f60a7deb34f 100644
--- a/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/api/AnthropicApi.java
+++ b/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/api/AnthropicApi.java
@@ -1542,7 +1542,7 @@ public record PingEvent(
 	}
 	// @formatter:on
 
-	public static class Builder {
+	public static final class Builder {
 
 		private String baseUrl = DEFAULT_BASE_URL;
 
diff --git a/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/api/AnthropicCacheOptions.java b/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/api/AnthropicCacheOptions.java
index b6739a705e4..f3e61e98fb0 100644
--- a/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/api/AnthropicCacheOptions.java
+++ b/models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/api/AnthropicCacheOptions.java
@@ -112,7 +112,7 @@ public String toString() {
 				+ ", messageTypeMinContentLengths=" + this.messageTypeMinContentLengths + '}';
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private final AnthropicCacheOptions options = new AnthropicCacheOptions();
 
diff --git a/models/spring-ai-azure-openai/src/main/java/org/springframework/ai/azure/openai/AzureOpenAiAudioTranscriptionOptions.java b/models/spring-ai-azure-openai/src/main/java/org/springframework/ai/azure/openai/AzureOpenAiAudioTranscriptionOptions.java
index e6ce7592bf8..d0c4941c418 100644
--- a/models/spring-ai-azure-openai/src/main/java/org/springframework/ai/azure/openai/AzureOpenAiAudioTranscriptionOptions.java
+++ b/models/spring-ai-azure-openai/src/main/java/org/springframework/ai/azure/openai/AzureOpenAiAudioTranscriptionOptions.java
@@ -255,7 +255,7 @@ public AudioTranscriptionTimestampGranularity getValue() {
 
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected AzureOpenAiAudioTranscriptionOptions options;
 
diff --git a/models/spring-ai-azure-openai/src/main/java/org/springframework/ai/azure/openai/AzureOpenAiChatOptions.java b/models/spring-ai-azure-openai/src/main/java/org/springframework/ai/azure/openai/AzureOpenAiChatOptions.java
index 8abbc35d702..2dcb1b5073f 100644
--- a/models/spring-ai-azure-openai/src/main/java/org/springframework/ai/azure/openai/AzureOpenAiChatOptions.java
+++ b/models/spring-ai-azure-openai/src/main/java/org/springframework/ai/azure/openai/AzureOpenAiChatOptions.java
@@ -573,7 +573,7 @@ public int hashCode() {
 				this.temperature, this.topP);
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected AzureOpenAiChatOptions options;
 
diff --git a/models/spring-ai-azure-openai/src/main/java/org/springframework/ai/azure/openai/AzureOpenAiEmbeddingOptions.java b/models/spring-ai-azure-openai/src/main/java/org/springframework/ai/azure/openai/AzureOpenAiEmbeddingOptions.java
index 52431f13bb2..adab81b249e 100644
--- a/models/spring-ai-azure-openai/src/main/java/org/springframework/ai/azure/openai/AzureOpenAiEmbeddingOptions.java
+++ b/models/spring-ai-azure-openai/src/main/java/org/springframework/ai/azure/openai/AzureOpenAiEmbeddingOptions.java
@@ -116,7 +116,7 @@ public com.azure.ai.openai.models.EmbeddingsOptions toAzureOptions(List<String>
 		return azureOptions;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private final AzureOpenAiEmbeddingOptions options = new AzureOpenAiEmbeddingOptions();
 
diff --git a/models/spring-ai-bedrock-converse/src/main/java/org/springframework/ai/bedrock/converse/BedrockChatOptions.java b/models/spring-ai-bedrock-converse/src/main/java/org/springframework/ai/bedrock/converse/BedrockChatOptions.java
index e1830e42959..ba0eceb2a62 100644
--- a/models/spring-ai-bedrock-converse/src/main/java/org/springframework/ai/bedrock/converse/BedrockChatOptions.java
+++ b/models/spring-ai-bedrock-converse/src/main/java/org/springframework/ai/bedrock/converse/BedrockChatOptions.java
@@ -269,7 +269,7 @@ public int hashCode() {
 				this.toolNames, this.toolContext, this.internalToolExecutionEnabled);
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private final BedrockChatOptions options = new BedrockChatOptions();
 
diff --git a/models/spring-ai-bedrock/src/main/java/org/springframework/ai/bedrock/cohere/BedrockCohereEmbeddingOptions.java b/models/spring-ai-bedrock/src/main/java/org/springframework/ai/bedrock/cohere/BedrockCohereEmbeddingOptions.java
index 2013425c335..600fb9912ba 100644
--- a/models/spring-ai-bedrock/src/main/java/org/springframework/ai/bedrock/cohere/BedrockCohereEmbeddingOptions.java
+++ b/models/spring-ai-bedrock/src/main/java/org/springframework/ai/bedrock/cohere/BedrockCohereEmbeddingOptions.java
@@ -84,7 +84,7 @@ public Integer getDimensions() {
 		return null;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private BedrockCohereEmbeddingOptions options = new BedrockCohereEmbeddingOptions();
 
diff --git a/models/spring-ai-bedrock/src/main/java/org/springframework/ai/bedrock/titan/BedrockTitanEmbeddingOptions.java b/models/spring-ai-bedrock/src/main/java/org/springframework/ai/bedrock/titan/BedrockTitanEmbeddingOptions.java
index 9f6237e0186..186d2743f59 100644
--- a/models/spring-ai-bedrock/src/main/java/org/springframework/ai/bedrock/titan/BedrockTitanEmbeddingOptions.java
+++ b/models/spring-ai-bedrock/src/main/java/org/springframework/ai/bedrock/titan/BedrockTitanEmbeddingOptions.java
@@ -62,7 +62,7 @@ public Integer getDimensions() {
 		return null;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private BedrockTitanEmbeddingOptions options = new BedrockTitanEmbeddingOptions();
 
diff --git a/models/spring-ai-bedrock/src/main/java/org/springframework/ai/bedrock/titan/api/TitanEmbeddingBedrockApi.java b/models/spring-ai-bedrock/src/main/java/org/springframework/ai/bedrock/titan/api/TitanEmbeddingBedrockApi.java
index bf65e288bb1..b97e860048d 100644
--- a/models/spring-ai-bedrock/src/main/java/org/springframework/ai/bedrock/titan/api/TitanEmbeddingBedrockApi.java
+++ b/models/spring-ai-bedrock/src/main/java/org/springframework/ai/bedrock/titan/api/TitanEmbeddingBedrockApi.java
@@ -139,7 +139,7 @@ public static Builder builder() {
 		/**
 		 * TitanEmbeddingRequest builder.
 		 */
-		public static class Builder {
+		public static final class Builder {
 
 			private String inputText;
 			private String inputImage;
diff --git a/models/spring-ai-deepseek/src/main/java/org/springframework/ai/deepseek/DeepSeekChatOptions.java b/models/spring-ai-deepseek/src/main/java/org/springframework/ai/deepseek/DeepSeekChatOptions.java
index b9c7a3d4962..d12c094fb87 100644
--- a/models/spring-ai-deepseek/src/main/java/org/springframework/ai/deepseek/DeepSeekChatOptions.java
+++ b/models/spring-ai-deepseek/src/main/java/org/springframework/ai/deepseek/DeepSeekChatOptions.java
@@ -382,7 +382,7 @@ public static DeepSeekChatOptions fromOptions(DeepSeekChatOptions fromOptions) {
 				.build();
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected DeepSeekChatOptions options;
 
diff --git a/models/spring-ai-deepseek/src/main/java/org/springframework/ai/deepseek/api/DeepSeekApi.java b/models/spring-ai-deepseek/src/main/java/org/springframework/ai/deepseek/api/DeepSeekApi.java
index f565c2ba26e..13415829854 100644
--- a/models/spring-ai-deepseek/src/main/java/org/springframework/ai/deepseek/api/DeepSeekApi.java
+++ b/models/spring-ai-deepseek/src/main/java/org/springframework/ai/deepseek/api/DeepSeekApi.java
@@ -905,7 +905,7 @@ public record ChunkChoice(// @formatter:off
 
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private String baseUrl = org.springframework.ai.deepseek.api.common.DeepSeekConstants.DEFAULT_BASE_URL;
 
diff --git a/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/ElevenLabsTextToSpeechModel.java b/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/ElevenLabsTextToSpeechModel.java
index 58f1b4ca363..68ed07568a8 100644
--- a/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/ElevenLabsTextToSpeechModel.java
+++ b/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/ElevenLabsTextToSpeechModel.java
@@ -181,7 +181,7 @@ public ElevenLabsTextToSpeechOptions getDefaultOptions() {
 		return this.defaultOptions;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private ElevenLabsApi elevenLabsApi;
 
diff --git a/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/ElevenLabsTextToSpeechOptions.java b/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/ElevenLabsTextToSpeechOptions.java
index b2037672c55..f1ab36fa842 100644
--- a/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/ElevenLabsTextToSpeechOptions.java
+++ b/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/ElevenLabsTextToSpeechOptions.java
@@ -324,7 +324,7 @@ public ElevenLabsTextToSpeechOptions copy() {
 			.build();
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private final ElevenLabsTextToSpeechOptions options = new ElevenLabsTextToSpeechOptions();
 
diff --git a/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/api/ElevenLabsApi.java b/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/api/ElevenLabsApi.java
index 407cf3bd9a9..10ce0349070 100644
--- a/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/api/ElevenLabsApi.java
+++ b/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/api/ElevenLabsApi.java
@@ -223,7 +223,7 @@ public record PronunciationDictionaryLocator(
 				@JsonProperty("version_id") String versionId) {
 		}
 
-		public static class Builder {
+		public static final class Builder {
 
 			private String text;
 
@@ -325,7 +325,7 @@ public SpeechRequest build() {
 	/**
 	 * Builder to construct {@link ElevenLabsApi} instance.
 	 */
-	public static class Builder {
+	public static final class Builder {
 
 		private String baseUrl = DEFAULT_BASE_URL;
 
diff --git a/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/api/ElevenLabsVoicesApi.java b/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/api/ElevenLabsVoicesApi.java
index 51df40c6d4f..3f6f6377937 100644
--- a/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/api/ElevenLabsVoicesApi.java
+++ b/models/spring-ai-elevenlabs/src/main/java/org/springframework/ai/elevenlabs/api/ElevenLabsVoicesApi.java
@@ -393,7 +393,7 @@ public record VerifiedVoiceLanguage(@JsonProperty("language") String language,
 	/**
 	 * Builder to construct {@link ElevenLabsVoicesApi} instance.
 	 */
-	public static class Builder {
+	public static final class Builder {
 
 		private String baseUrl = DEFAULT_BASE_URL;
 
diff --git a/models/spring-ai-google-genai-embedding/src/main/java/org/springframework/ai/google/genai/GoogleGenAiEmbeddingConnectionDetails.java b/models/spring-ai-google-genai-embedding/src/main/java/org/springframework/ai/google/genai/GoogleGenAiEmbeddingConnectionDetails.java
index 143e9095f26..8dafa917aa7 100644
--- a/models/spring-ai-google-genai-embedding/src/main/java/org/springframework/ai/google/genai/GoogleGenAiEmbeddingConnectionDetails.java
+++ b/models/spring-ai-google-genai-embedding/src/main/java/org/springframework/ai/google/genai/GoogleGenAiEmbeddingConnectionDetails.java
@@ -101,7 +101,7 @@ public String getModelEndpointName(String modelName) {
 		return modelName;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		/**
 		 * Your project ID.
diff --git a/models/spring-ai-google-genai-embedding/src/main/java/org/springframework/ai/google/genai/text/GoogleGenAiTextEmbeddingOptions.java b/models/spring-ai-google-genai-embedding/src/main/java/org/springframework/ai/google/genai/text/GoogleGenAiTextEmbeddingOptions.java
index 2f21a2ecca2..e402368ca24 100644
--- a/models/spring-ai-google-genai-embedding/src/main/java/org/springframework/ai/google/genai/text/GoogleGenAiTextEmbeddingOptions.java
+++ b/models/spring-ai-google-genai-embedding/src/main/java/org/springframework/ai/google/genai/text/GoogleGenAiTextEmbeddingOptions.java
@@ -170,7 +170,7 @@ public enum TaskType {
 
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected GoogleGenAiTextEmbeddingOptions options;
 
diff --git a/models/spring-ai-google-genai/src/main/java/org/springframework/ai/google/genai/GoogleGenAiChatOptions.java b/models/spring-ai-google-genai/src/main/java/org/springframework/ai/google/genai/GoogleGenAiChatOptions.java
index dac53757e0a..d242c9ce2e0 100644
--- a/models/spring-ai-google-genai/src/main/java/org/springframework/ai/google/genai/GoogleGenAiChatOptions.java
+++ b/models/spring-ai-google-genai/src/main/java/org/springframework/ai/google/genai/GoogleGenAiChatOptions.java
@@ -488,7 +488,7 @@ public enum TransportType {
 
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private GoogleGenAiChatOptions options = new GoogleGenAiChatOptions();
 
diff --git a/models/spring-ai-google-genai/src/main/java/org/springframework/ai/google/genai/common/GoogleGenAiSafetySetting.java b/models/spring-ai-google-genai/src/main/java/org/springframework/ai/google/genai/common/GoogleGenAiSafetySetting.java
index dd11a3ba680..b87b8f55371 100644
--- a/models/spring-ai-google-genai/src/main/java/org/springframework/ai/google/genai/common/GoogleGenAiSafetySetting.java
+++ b/models/spring-ai-google-genai/src/main/java/org/springframework/ai/google/genai/common/GoogleGenAiSafetySetting.java
@@ -156,7 +156,7 @@ public int hashCode() {
 		return result;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private HarmCategory category = HarmCategory.HARM_CATEGORY_UNSPECIFIED;
 
diff --git a/models/spring-ai-minimax/src/main/java/org/springframework/ai/minimax/MiniMaxChatOptions.java b/models/spring-ai-minimax/src/main/java/org/springframework/ai/minimax/MiniMaxChatOptions.java
index 3ef50450d9a..a669e7e7adc 100644
--- a/models/spring-ai-minimax/src/main/java/org/springframework/ai/minimax/MiniMaxChatOptions.java
+++ b/models/spring-ai-minimax/src/main/java/org/springframework/ai/minimax/MiniMaxChatOptions.java
@@ -397,7 +397,7 @@ public MiniMaxChatOptions copy() {
 		return fromOptions(this);
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected MiniMaxChatOptions options;
 
diff --git a/models/spring-ai-minimax/src/main/java/org/springframework/ai/minimax/MiniMaxEmbeddingOptions.java b/models/spring-ai-minimax/src/main/java/org/springframework/ai/minimax/MiniMaxEmbeddingOptions.java
index 2fe66ea3483..2ed1bb4fcc6 100644
--- a/models/spring-ai-minimax/src/main/java/org/springframework/ai/minimax/MiniMaxEmbeddingOptions.java
+++ b/models/spring-ai-minimax/src/main/java/org/springframework/ai/minimax/MiniMaxEmbeddingOptions.java
@@ -59,7 +59,7 @@ public Integer getDimensions() {
 		return null;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected MiniMaxEmbeddingOptions options;
 
diff --git a/models/spring-ai-oci-genai/src/main/java/org/springframework/ai/oci/OCIEmbeddingOptions.java b/models/spring-ai-oci-genai/src/main/java/org/springframework/ai/oci/OCIEmbeddingOptions.java
index 73fda2500fe..511a9a14814 100644
--- a/models/spring-ai-oci-genai/src/main/java/org/springframework/ai/oci/OCIEmbeddingOptions.java
+++ b/models/spring-ai-oci-genai/src/main/java/org/springframework/ai/oci/OCIEmbeddingOptions.java
@@ -84,7 +84,7 @@ public void setTruncate(EmbedTextDetails.Truncate truncate) {
 		this.truncate = truncate;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private final OCIEmbeddingOptions options = new OCIEmbeddingOptions();
 
diff --git a/models/spring-ai-oci-genai/src/main/java/org/springframework/ai/oci/cohere/OCICohereChatOptions.java b/models/spring-ai-oci-genai/src/main/java/org/springframework/ai/oci/cohere/OCICohereChatOptions.java
index 62e5867b350..8662362ea3a 100644
--- a/models/spring-ai-oci-genai/src/main/java/org/springframework/ai/oci/cohere/OCICohereChatOptions.java
+++ b/models/spring-ai-oci-genai/src/main/java/org/springframework/ai/oci/cohere/OCICohereChatOptions.java
@@ -294,7 +294,7 @@ public boolean equals(Object o) {
 				&& Objects.equals(this.documents, that.documents) && Objects.equals(this.tools, that.tools);
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected OCICohereChatOptions chatOptions;
 
diff --git a/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaApi.java b/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaApi.java
index 4cbf1357c59..a541b4a1588 100644
--- a/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaApi.java
+++ b/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaApi.java
@@ -330,7 +330,7 @@ public ToolCallFunction(String name, Map<String, Object> arguments) {
 
 		}
 
-		public static class Builder {
+		public static final class Builder {
 
 			private final Role role;
 			private String content;
@@ -466,7 +466,7 @@ public Function(String description, String name, String jsonSchema) {
 			}
 		}
 
-		public static class Builder {
+		public static final class Builder {
 
 			private final String model;
 			private List<Message> messages = List.of();
@@ -750,7 +750,7 @@ public record ProgressResponse(
 			@JsonProperty("completed") Long completed
 	) { }
 
-	public static class Builder {
+	public static final class Builder {
 
 		private String baseUrl = OllamaApiConstants.DEFAULT_BASE_URL;
 
diff --git a/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaChatOptions.java b/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaChatOptions.java
index fe8b11e3c72..2bcbce8101a 100644
--- a/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaChatOptions.java
+++ b/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaChatOptions.java
@@ -858,7 +858,7 @@ public int hashCode() {
 				this.toolContext);
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private final OllamaChatOptions options = new OllamaChatOptions();
 
diff --git a/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaEmbeddingOptions.java b/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaEmbeddingOptions.java
index 3b29ccf6179..24bb0618f5b 100644
--- a/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaEmbeddingOptions.java
+++ b/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaEmbeddingOptions.java
@@ -338,7 +338,7 @@ public int hashCode() {
 		return Objects.hash(this.model, this.keepAlive, this.truncate);
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private final OllamaEmbeddingOptions options = new OllamaEmbeddingOptions();
 
diff --git a/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaOptions.java b/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaOptions.java
index cb9d043649d..84c0752654b 100644
--- a/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaOptions.java
+++ b/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/api/OllamaOptions.java
@@ -947,7 +947,7 @@ public int hashCode() {
 	}
 
 	@Deprecated
-	public static class Builder {
+	public static final class Builder {
 
 		private final OllamaOptions options = new OllamaOptions();
 
diff --git a/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/management/ModelManagementOptions.java b/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/management/ModelManagementOptions.java
index 3e5148e6b97..dc3bffe9463 100644
--- a/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/management/ModelManagementOptions.java
+++ b/models/spring-ai-ollama/src/main/java/org/springframework/ai/ollama/management/ModelManagementOptions.java
@@ -41,7 +41,7 @@ public static Builder builder() {
 		return new Builder();
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private PullModelStrategy pullModelStrategy = PullModelStrategy.NEVER;
 
diff --git a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiAudioSpeechOptions.java b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiAudioSpeechOptions.java
index 6e5d1a8eccc..7b293a104b7 100644
--- a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiAudioSpeechOptions.java
+++ b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiAudioSpeechOptions.java
@@ -188,7 +188,7 @@ public String toString() {
 				+ this.speed + '}';
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private final OpenAiAudioSpeechOptions options = new OpenAiAudioSpeechOptions();
 
diff --git a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiAudioTranscriptionOptions.java b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiAudioTranscriptionOptions.java
index a03688d04b9..097f8e2b254 100644
--- a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiAudioTranscriptionOptions.java
+++ b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiAudioTranscriptionOptions.java
@@ -170,7 +170,7 @@ else if (!this.responseFormat.equals(other.responseFormat)) {
 		return true;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected OpenAiAudioTranscriptionOptions options;
 
diff --git a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiChatOptions.java b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiChatOptions.java
index 14b5ba42536..1f2ceb8abcc 100644
--- a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiChatOptions.java
+++ b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiChatOptions.java
@@ -673,7 +673,7 @@ public String toString() {
 		return "OpenAiChatOptions: " + ModelOptionsUtils.toJsonString(this);
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected OpenAiChatOptions options;
 
diff --git a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiEmbeddingOptions.java b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiEmbeddingOptions.java
index 54ba275dd61..cfad3710059 100644
--- a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiEmbeddingOptions.java
+++ b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/OpenAiEmbeddingOptions.java
@@ -89,7 +89,7 @@ public void setUser(String user) {
 		this.user = user;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected OpenAiEmbeddingOptions options;
 
diff --git a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiApi.java b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiApi.java
index f7e72246e97..8064b070aab 100644
--- a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiApi.java
+++ b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiApi.java
@@ -1957,7 +1957,7 @@ public record EmbeddingList<T>(// @formatter:off
 			@JsonProperty("usage") Usage usage) { // @formatter:on
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		public Builder() {
 		}
diff --git a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiAudioApi.java b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiAudioApi.java
index 9177c365a8d..cd5b3e89d8f 100644
--- a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiAudioApi.java
+++ b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiAudioApi.java
@@ -435,7 +435,7 @@ public String getValue() {
 		/**
 		 * Builder for the SpeechRequest.
 		 */
-		public static class Builder {
+		public static final class Builder {
 
 			private String model = TtsModel.TTS_1.getValue();
 
@@ -550,7 +550,7 @@ public String getValue() {
 
 		}
 
-		public static class Builder {
+		public static final class Builder {
 
 			private byte[] file;
 
@@ -653,7 +653,7 @@ public static Builder builder() {
 			return new Builder();
 		}
 
-		public static class Builder {
+		public static final class Builder {
 
 			private byte[] file;
 
@@ -790,7 +790,7 @@ public record Segment(
 	/**
 	 * Builder to construct {@link OpenAiAudioApi} instance.
 	 */
-	public static class Builder {
+	public static final class Builder {
 
 		private String baseUrl = OpenAiApiConstants.DEFAULT_BASE_URL;
 
diff --git a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiFileApi.java b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiFileApi.java
index fa043db373b..8004d8f6686 100644
--- a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiFileApi.java
+++ b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiFileApi.java
@@ -201,7 +201,7 @@ public static Builder builder() {
 			return new Builder();
 		}
 
-		public static class Builder {
+		public static final class Builder {
 
 			private byte[] file;
 
@@ -253,7 +253,7 @@ public static Builder builder() {
 			return new Builder();
 		}
 
-		public static class Builder {
+		public static final class Builder {
 
 			private String after;
 
@@ -326,7 +326,7 @@ public record DeleteFileResponse(
 		// @formatter:on
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private String baseUrl = OpenAiApiConstants.DEFAULT_BASE_URL;
 
diff --git a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiImageApi.java b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiImageApi.java
index 986f82f7622..fe82e30e56b 100644
--- a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiImageApi.java
+++ b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiImageApi.java
@@ -162,7 +162,7 @@ public record Data(@JsonProperty("url") String url, @JsonProperty("b64_json") St
 	/**
 	 * Builder to construct {@link OpenAiImageApi} instance.
 	 */
-	public static class Builder {
+	public static final class Builder {
 
 		private String baseUrl = OpenAiApiConstants.DEFAULT_BASE_URL;
 
diff --git a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiModerationApi.java b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiModerationApi.java
index 151cd007302..fc05811c5bb 100644
--- a/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiModerationApi.java
+++ b/models/spring-ai-openai/src/main/java/org/springframework/ai/openai/api/OpenAiModerationApi.java
@@ -172,7 +172,7 @@ public record Data(@JsonProperty("url") String url, @JsonProperty("b64_json") St
 	/**
 	 * Builder to construct {@link OpenAiModerationApi} instance.
 	 */
-	public static class Builder {
+	public static final class Builder {
 
 		private String baseUrl = OpenAiApiConstants.DEFAULT_BASE_URL;
 
diff --git a/models/spring-ai-postgresml/src/main/java/org/springframework/ai/postgresml/PostgresMlEmbeddingOptions.java b/models/spring-ai-postgresml/src/main/java/org/springframework/ai/postgresml/PostgresMlEmbeddingOptions.java
index 847fdcf7e00..e28c7a6cbdb 100644
--- a/models/spring-ai-postgresml/src/main/java/org/springframework/ai/postgresml/PostgresMlEmbeddingOptions.java
+++ b/models/spring-ai-postgresml/src/main/java/org/springframework/ai/postgresml/PostgresMlEmbeddingOptions.java
@@ -109,7 +109,7 @@ public Integer getDimensions() {
 		return null;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected PostgresMlEmbeddingOptions options;
 
diff --git a/models/spring-ai-stability-ai/src/main/java/org/springframework/ai/stabilityai/api/StabilityAiApi.java b/models/spring-ai-stability-ai/src/main/java/org/springframework/ai/stabilityai/api/StabilityAiApi.java
index 2d55c659807..d34927c52d1 100644
--- a/models/spring-ai-stability-ai/src/main/java/org/springframework/ai/stabilityai/api/StabilityAiApi.java
+++ b/models/spring-ai-stability-ai/src/main/java/org/springframework/ai/stabilityai/api/StabilityAiApi.java
@@ -112,7 +112,7 @@ public record TextPrompts(@JsonProperty("text") String text, @JsonProperty("weig
 
 		}
 
-		public static class Builder {
+		public static final class Builder {
 
 			List<TextPrompts> textPrompts;
 
diff --git a/models/spring-ai-vertex-ai-embedding/src/main/java/org/springframework/ai/vertexai/embedding/VertexAiEmbeddingConnectionDetails.java b/models/spring-ai-vertex-ai-embedding/src/main/java/org/springframework/ai/vertexai/embedding/VertexAiEmbeddingConnectionDetails.java
index d678c92184d..9cd8f1418d0 100644
--- a/models/spring-ai-vertex-ai-embedding/src/main/java/org/springframework/ai/vertexai/embedding/VertexAiEmbeddingConnectionDetails.java
+++ b/models/spring-ai-vertex-ai-embedding/src/main/java/org/springframework/ai/vertexai/embedding/VertexAiEmbeddingConnectionDetails.java
@@ -94,7 +94,7 @@ public PredictionServiceSettings getPredictionServiceSettings() {
 		return this.predictionServiceSettings;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		/**
 		 * The Vertex AI embedding endpoint.
diff --git a/models/spring-ai-vertex-ai-embedding/src/main/java/org/springframework/ai/vertexai/embedding/multimodal/VertexAiMultimodalEmbeddingOptions.java b/models/spring-ai-vertex-ai-embedding/src/main/java/org/springframework/ai/vertexai/embedding/multimodal/VertexAiMultimodalEmbeddingOptions.java
index ada536e66ae..8c63da18b91 100644
--- a/models/spring-ai-vertex-ai-embedding/src/main/java/org/springframework/ai/vertexai/embedding/multimodal/VertexAiMultimodalEmbeddingOptions.java
+++ b/models/spring-ai-vertex-ai-embedding/src/main/java/org/springframework/ai/vertexai/embedding/multimodal/VertexAiMultimodalEmbeddingOptions.java
@@ -148,7 +148,7 @@ public void setVideoIntervalSec(Integer videoIntervalSec) {
 		this.videoIntervalSec = videoIntervalSec;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected VertexAiMultimodalEmbeddingOptions options;
 
diff --git a/models/spring-ai-vertex-ai-embedding/src/main/java/org/springframework/ai/vertexai/embedding/text/VertexAiTextEmbeddingOptions.java b/models/spring-ai-vertex-ai-embedding/src/main/java/org/springframework/ai/vertexai/embedding/text/VertexAiTextEmbeddingOptions.java
index 4f384b35b26..7db94396f63 100644
--- a/models/spring-ai-vertex-ai-embedding/src/main/java/org/springframework/ai/vertexai/embedding/text/VertexAiTextEmbeddingOptions.java
+++ b/models/spring-ai-vertex-ai-embedding/src/main/java/org/springframework/ai/vertexai/embedding/text/VertexAiTextEmbeddingOptions.java
@@ -169,7 +169,7 @@ public enum TaskType {
 
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected VertexAiTextEmbeddingOptions options;
 
diff --git a/models/spring-ai-vertex-ai-gemini/src/main/java/org/springframework/ai/vertexai/gemini/VertexAiGeminiChatOptions.java b/models/spring-ai-vertex-ai-gemini/src/main/java/org/springframework/ai/vertexai/gemini/VertexAiGeminiChatOptions.java
index 2c7562fb2c6..bbdf7cdbd9a 100644
--- a/models/spring-ai-vertex-ai-gemini/src/main/java/org/springframework/ai/vertexai/gemini/VertexAiGeminiChatOptions.java
+++ b/models/spring-ai-vertex-ai-gemini/src/main/java/org/springframework/ai/vertexai/gemini/VertexAiGeminiChatOptions.java
@@ -428,7 +428,7 @@ public enum TransportType {
 
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private VertexAiGeminiChatOptions options = new VertexAiGeminiChatOptions();
 
diff --git a/models/spring-ai-vertex-ai-gemini/src/main/java/org/springframework/ai/vertexai/gemini/common/VertexAiGeminiSafetySetting.java b/models/spring-ai-vertex-ai-gemini/src/main/java/org/springframework/ai/vertexai/gemini/common/VertexAiGeminiSafetySetting.java
index d693676f503..7b38256dd9e 100644
--- a/models/spring-ai-vertex-ai-gemini/src/main/java/org/springframework/ai/vertexai/gemini/common/VertexAiGeminiSafetySetting.java
+++ b/models/spring-ai-vertex-ai-gemini/src/main/java/org/springframework/ai/vertexai/gemini/common/VertexAiGeminiSafetySetting.java
@@ -139,7 +139,7 @@ public int hashCode() {
 		return result;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private HarmCategory category = HarmCategory.HARM_CATEGORY_UNSPECIFIED;
 
diff --git a/models/spring-ai-zhipuai/src/main/java/org/springframework/ai/zhipuai/ZhiPuAiChatOptions.java b/models/spring-ai-zhipuai/src/main/java/org/springframework/ai/zhipuai/ZhiPuAiChatOptions.java
index d79557d534f..a5389214a67 100644
--- a/models/spring-ai-zhipuai/src/main/java/org/springframework/ai/zhipuai/ZhiPuAiChatOptions.java
+++ b/models/spring-ai-zhipuai/src/main/java/org/springframework/ai/zhipuai/ZhiPuAiChatOptions.java
@@ -459,7 +459,7 @@ public ToolCallingChatOptions merge(ChatOptions options) {
 		return builder.build();
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected ZhiPuAiChatOptions options;
 
diff --git a/models/spring-ai-zhipuai/src/main/java/org/springframework/ai/zhipuai/ZhiPuAiEmbeddingOptions.java b/models/spring-ai-zhipuai/src/main/java/org/springframework/ai/zhipuai/ZhiPuAiEmbeddingOptions.java
index fc2c10161e4..1cf528be727 100644
--- a/models/spring-ai-zhipuai/src/main/java/org/springframework/ai/zhipuai/ZhiPuAiEmbeddingOptions.java
+++ b/models/spring-ai-zhipuai/src/main/java/org/springframework/ai/zhipuai/ZhiPuAiEmbeddingOptions.java
@@ -66,7 +66,7 @@ public Integer getDimensions() {
 		return this.dimensions;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		protected ZhiPuAiEmbeddingOptions options;
 
diff --git a/models/spring-ai-zhipuai/src/main/java/org/springframework/ai/zhipuai/api/ZhiPuAiApi.java b/models/spring-ai-zhipuai/src/main/java/org/springframework/ai/zhipuai/api/ZhiPuAiApi.java
index cbc952bea94..c5a99f99eb3 100644
--- a/models/spring-ai-zhipuai/src/main/java/org/springframework/ai/zhipuai/api/ZhiPuAiApi.java
+++ b/models/spring-ai-zhipuai/src/main/java/org/springframework/ai/zhipuai/api/ZhiPuAiApi.java
@@ -1207,7 +1207,7 @@ public record EmbeddingList<T>(// @formatter:off
 			@JsonProperty("usage") Usage usage) { // @formatter:on
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private Builder() {
 		}
diff --git a/spring-ai-client-chat/src/main/java/org/springframework/ai/chat/client/advisor/DefaultAroundAdvisorChain.java b/spring-ai-client-chat/src/main/java/org/springframework/ai/chat/client/advisor/DefaultAroundAdvisorChain.java
index 67da37aea82..310687a2f87 100644
--- a/spring-ai-client-chat/src/main/java/org/springframework/ai/chat/client/advisor/DefaultAroundAdvisorChain.java
+++ b/spring-ai-client-chat/src/main/java/org/springframework/ai/chat/client/advisor/DefaultAroundAdvisorChain.java
@@ -148,7 +148,7 @@ public ObservationRegistry getObservationRegistry() {
 		return this.observationRegistry;
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private final ObservationRegistry observationRegistry;
 
diff --git a/spring-ai-commons/src/main/java/org/springframework/ai/document/Document.java b/spring-ai-commons/src/main/java/org/springframework/ai/document/Document.java
index d274592fc50..ee419f81d69 100644
--- a/spring-ai-commons/src/main/java/org/springframework/ai/document/Document.java
+++ b/spring-ai-commons/src/main/java/org/springframework/ai/document/Document.java
@@ -288,7 +288,7 @@ public String toString() {
 				+ ", metadata=" + this.metadata + ", score=" + this.score + '}';
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private String id;
 
diff --git a/spring-ai-commons/src/main/java/org/springframework/ai/reader/ExtractedTextFormatter.java b/spring-ai-commons/src/main/java/org/springframework/ai/reader/ExtractedTextFormatter.java
index 0ad3e3290b3..73ed8153ee1 100644
--- a/spring-ai-commons/src/main/java/org/springframework/ai/reader/ExtractedTextFormatter.java
+++ b/spring-ai-commons/src/main/java/org/springframework/ai/reader/ExtractedTextFormatter.java
@@ -218,7 +218,7 @@ public String format(String pageText, int pageNumber) {
 	 *
 	 * @see ExtractedTextFormatter
 	 */
-	public static class Builder {
+	public static final class Builder {
 
 		private boolean leftAlignment = false;
 
diff --git a/spring-ai-model/src/main/java/org/springframework/ai/audio/tts/DefaultTextToSpeechOptions.java b/spring-ai-model/src/main/java/org/springframework/ai/audio/tts/DefaultTextToSpeechOptions.java
index 73b7cfb890a..2b832d38227 100644
--- a/spring-ai-model/src/main/java/org/springframework/ai/audio/tts/DefaultTextToSpeechOptions.java
+++ b/spring-ai-model/src/main/java/org/springframework/ai/audio/tts/DefaultTextToSpeechOptions.java
@@ -96,7 +96,7 @@ public DefaultTextToSpeechOptions copy() {
 		return new Builder(this).build();
 	}
 
-	public static class Builder implements TextToSpeechOptions.Builder {
+	public static final class Builder implements TextToSpeechOptions.Builder {
 
 		private String model;
 
diff --git a/spring-ai-model/src/main/java/org/springframework/ai/chat/messages/SystemMessage.java b/spring-ai-model/src/main/java/org/springframework/ai/chat/messages/SystemMessage.java
index 8a187add90e..91d80fc7999 100644
--- a/spring-ai-model/src/main/java/org/springframework/ai/chat/messages/SystemMessage.java
+++ b/spring-ai-model/src/main/java/org/springframework/ai/chat/messages/SystemMessage.java
@@ -89,7 +89,7 @@ public static Builder builder() {
 		return new Builder();
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		@Nullable
 		private String textContent;
diff --git a/spring-ai-model/src/main/java/org/springframework/ai/chat/messages/UserMessage.java b/spring-ai-model/src/main/java/org/springframework/ai/chat/messages/UserMessage.java
index fc005392c34..a75bec61472 100644
--- a/spring-ai-model/src/main/java/org/springframework/ai/chat/messages/UserMessage.java
+++ b/spring-ai-model/src/main/java/org/springframework/ai/chat/messages/UserMessage.java
@@ -84,7 +84,7 @@ public static Builder builder() {
 		return new Builder();
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		@Nullable
 		private String textContent;
diff --git a/spring-ai-model/src/main/java/org/springframework/ai/chat/metadata/ChatResponseMetadata.java b/spring-ai-model/src/main/java/org/springframework/ai/chat/metadata/ChatResponseMetadata.java
index b8392c7ede2..e51ed29f898 100644
--- a/spring-ai-model/src/main/java/org/springframework/ai/chat/metadata/ChatResponseMetadata.java
+++ b/spring-ai-model/src/main/java/org/springframework/ai/chat/metadata/ChatResponseMetadata.java
@@ -119,7 +119,7 @@ public String toString() {
 		return AI_METADATA_STRING.formatted(getId(), getUsage(), getRateLimit());
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private final ChatResponseMetadata chatResponseMetadata;
 
diff --git a/spring-ai-model/src/main/java/org/springframework/ai/chat/prompt/Prompt.java b/spring-ai-model/src/main/java/org/springframework/ai/chat/prompt/Prompt.java
index 8c6c66197a8..c1cbc829df3 100644
--- a/spring-ai-model/src/main/java/org/springframework/ai/chat/prompt/Prompt.java
+++ b/spring-ai-model/src/main/java/org/springframework/ai/chat/prompt/Prompt.java
@@ -272,7 +272,7 @@ public static Builder builder() {
 		return new Builder();
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		@Nullable
 		private String content;
diff --git a/spring-ai-model/src/main/java/org/springframework/ai/model/tool/DefaultToolCallingChatOptions.java b/spring-ai-model/src/main/java/org/springframework/ai/model/tool/DefaultToolCallingChatOptions.java
index 870db6931b9..e088994139b 100644
--- a/spring-ai-model/src/main/java/org/springframework/ai/model/tool/DefaultToolCallingChatOptions.java
+++ b/spring-ai-model/src/main/java/org/springframework/ai/model/tool/DefaultToolCallingChatOptions.java
@@ -224,7 +224,7 @@ public static Builder builder() {
 	/**
 	 * Default implementation of {@link ToolCallingChatOptions.Builder}.
 	 */
-	public static class Builder implements ToolCallingChatOptions.Builder {
+	public static final class Builder implements ToolCallingChatOptions.Builder {
 
 		private final DefaultToolCallingChatOptions options = new DefaultToolCallingChatOptions();
 
diff --git a/spring-ai-model/src/main/java/org/springframework/ai/model/transformer/KeywordMetadataEnricher.java b/spring-ai-model/src/main/java/org/springframework/ai/model/transformer/KeywordMetadataEnricher.java
index bf9b38fca70..ee9ebb492b2 100644
--- a/spring-ai-model/src/main/java/org/springframework/ai/model/transformer/KeywordMetadataEnricher.java
+++ b/spring-ai-model/src/main/java/org/springframework/ai/model/transformer/KeywordMetadataEnricher.java
@@ -102,7 +102,7 @@ public static Builder builder(ChatModel chatModel) {
 		return new Builder(chatModel);
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private final ChatModel chatModel;
 
diff --git a/spring-ai-model/src/main/java/org/springframework/ai/moderation/Categories.java b/spring-ai-model/src/main/java/org/springframework/ai/moderation/Categories.java
index 23fa93cca61..64ddbbfe402 100644
--- a/spring-ai-model/src/main/java/org/springframework/ai/moderation/Categories.java
+++ b/spring-ai-model/src/main/java/org/springframework/ai/moderation/Categories.java
@@ -186,7 +186,7 @@ public String toString() {
 				+ ", financial=" + this.financial + ", law=" + this.law + ", pii=" + this.pii + '}';
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private boolean sexual;
 
diff --git a/spring-ai-model/src/main/java/org/springframework/ai/moderation/CategoryScores.java b/spring-ai-model/src/main/java/org/springframework/ai/moderation/CategoryScores.java
index 328e2e8682e..eb2facab630 100644
--- a/spring-ai-model/src/main/java/org/springframework/ai/moderation/CategoryScores.java
+++ b/spring-ai-model/src/main/java/org/springframework/ai/moderation/CategoryScores.java
@@ -193,7 +193,7 @@ public String toString() {
 				+ ", financial=" + this.financial + ", law=" + this.law + ", pii=" + this.pii + '}';
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private double sexual;
 
diff --git a/spring-ai-model/src/main/java/org/springframework/ai/moderation/Moderation.java b/spring-ai-model/src/main/java/org/springframework/ai/moderation/Moderation.java
index 18bb5f9d64d..7e2e503d04c 100644
--- a/spring-ai-model/src/main/java/org/springframework/ai/moderation/Moderation.java
+++ b/spring-ai-model/src/main/java/org/springframework/ai/moderation/Moderation.java
@@ -83,7 +83,7 @@ public int hashCode() {
 		return Objects.hash(this.id, this.model, this.results);
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private String id;
 
diff --git a/spring-ai-model/src/main/java/org/springframework/ai/moderation/ModerationResult.java b/spring-ai-model/src/main/java/org/springframework/ai/moderation/ModerationResult.java
index 857a3a273ef..5ccfb6da947 100644
--- a/spring-ai-model/src/main/java/org/springframework/ai/moderation/ModerationResult.java
+++ b/spring-ai-model/src/main/java/org/springframework/ai/moderation/ModerationResult.java
@@ -92,7 +92,7 @@ public String toString() {
 				+ this.categoryScores + '}';
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private boolean flagged;
 
diff --git a/spring-ai-model/src/main/java/org/springframework/ai/tool/execution/DefaultToolExecutionExceptionProcessor.java b/spring-ai-model/src/main/java/org/springframework/ai/tool/execution/DefaultToolExecutionExceptionProcessor.java
index b42f4f63af9..5efe177a8d1 100644
--- a/spring-ai-model/src/main/java/org/springframework/ai/tool/execution/DefaultToolExecutionExceptionProcessor.java
+++ b/spring-ai-model/src/main/java/org/springframework/ai/tool/execution/DefaultToolExecutionExceptionProcessor.java
@@ -85,7 +85,7 @@ public static Builder builder() {
 		return new Builder();
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private boolean alwaysThrow = DEFAULT_ALWAYS_THROW;
 
diff --git a/spring-ai-model/src/main/java/org/springframework/ai/tool/resolution/SpringBeanToolCallbackResolver.java b/spring-ai-model/src/main/java/org/springframework/ai/tool/resolution/SpringBeanToolCallbackResolver.java
index e15a9ebf2b1..e58a2180721 100644
--- a/spring-ai-model/src/main/java/org/springframework/ai/tool/resolution/SpringBeanToolCallbackResolver.java
+++ b/spring-ai-model/src/main/java/org/springframework/ai/tool/resolution/SpringBeanToolCallbackResolver.java
@@ -197,7 +197,7 @@ public static Builder builder() {
 		return new Builder();
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private GenericApplicationContext applicationContext;
 
diff --git a/spring-ai-rag/src/main/java/org/springframework/ai/rag/generation/augmentation/ContextualQueryAugmenter.java b/spring-ai-rag/src/main/java/org/springframework/ai/rag/generation/augmentation/ContextualQueryAugmenter.java
index e4918389502..6cf814583d0 100644
--- a/spring-ai-rag/src/main/java/org/springframework/ai/rag/generation/augmentation/ContextualQueryAugmenter.java
+++ b/spring-ai-rag/src/main/java/org/springframework/ai/rag/generation/augmentation/ContextualQueryAugmenter.java
@@ -136,7 +136,7 @@ public static Builder builder() {
 		return new Builder();
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private PromptTemplate promptTemplate;
 
diff --git a/spring-ai-vector-store/src/main/java/org/springframework/ai/vectorstore/SearchRequest.java b/spring-ai-vector-store/src/main/java/org/springframework/ai/vectorstore/SearchRequest.java
index 4eae298a86d..7ed36eeff24 100644
--- a/spring-ai-vector-store/src/main/java/org/springframework/ai/vectorstore/SearchRequest.java
+++ b/spring-ai-vector-store/src/main/java/org/springframework/ai/vectorstore/SearchRequest.java
@@ -138,7 +138,7 @@ public static Builder builder() {
 	/**
 	 * SearchRequest Builder.
 	 */
-	public static class Builder {
+	public static final class Builder {
 
 		private final SearchRequest searchRequest = new SearchRequest();
 
diff --git a/spring-ai-vector-store/src/main/java/org/springframework/ai/vectorstore/observation/VectorStoreObservationContext.java b/spring-ai-vector-store/src/main/java/org/springframework/ai/vectorstore/observation/VectorStoreObservationContext.java
index dbd61435bab..5a8c3854543 100644
--- a/spring-ai-vector-store/src/main/java/org/springframework/ai/vectorstore/observation/VectorStoreObservationContext.java
+++ b/spring-ai-vector-store/src/main/java/org/springframework/ai/vectorstore/observation/VectorStoreObservationContext.java
@@ -177,7 +177,7 @@ public String value() {
 
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private final VectorStoreObservationContext context;
 
diff --git a/vector-stores/spring-ai-chroma-store/src/main/java/org/springframework/ai/chroma/vectorstore/ChromaApi.java b/vector-stores/spring-ai-chroma-store/src/main/java/org/springframework/ai/chroma/vectorstore/ChromaApi.java
index 79166c0c2a1..9403ee26a6e 100644
--- a/vector-stores/spring-ai-chroma-store/src/main/java/org/springframework/ai/chroma/vectorstore/ChromaApi.java
+++ b/vector-stores/spring-ai-chroma-store/src/main/java/org/springframework/ai/chroma/vectorstore/ChromaApi.java
@@ -628,7 +628,7 @@ private static class CollectionList extends ArrayList<Collection> {
 
 	}
 
-	public static class Builder {
+	public static final class Builder {
 
 		private String baseUrl = ChromaApiConstants.DEFAULT_BASE_URL;