fix: replace deprecated Nullable annotation with jspecify's Nullable

Signed-off-by: Wenli Tian <jamespud9@gmail.com>

Author: jamespud

advisors/spring-ai-advisors-vector-store/src/main/java/org/springframework/ai/chat/client/advisor/vectorstore/QuestionAnswerAdvisor.java

@@ -36,7 +36,7 @@
 import org.springframework.ai.vectorstore.VectorStore;
 import org.springframework.ai.vectorstore.filter.Filter;
 import org.springframework.ai.vectorstore.filter.FilterExpressionTextParser;
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 
@@ -150,8 +150,7 @@ public ChatClientResponse after(ChatClientResponse chatClientResponse, AdvisorCh
 			.build();
 	}
 
-	@Nullable
-	protected Filter.Expression doGetFilterExpression(Map<String, Object> context) {
+	protected Filter.@Nullable Expression doGetFilterExpression(Map<String, Object> context) {
 		if (!context.containsKey(FILTER_EXPRESSION)
 				|| !StringUtils.hasText(context.get(FILTER_EXPRESSION).toString())) {
 			return this.searchRequest.getFilterExpression();

auto-configurations/models/chat/memory/repository/spring-ai-autoconfigure-model-chat-memory-repository-cassandra/src/main/java/org/springframework/ai/model/chat/memory/repository/cassandra/autoconfigure/CassandraChatMemoryRepositoryProperties.java

@@ -23,7 +23,7 @@
 
 import org.springframework.ai.chat.memory.repository.cassandra.CassandraChatMemoryRepositoryConfig;
 import org.springframework.boot.context.properties.ConfigurationProperties;
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * Configuration properties for Cassandra chat memory.

mcp/common/src/main/java/org/springframework/ai/mcp/AsyncMcpToolCallback.java

@@ -32,7 +32,7 @@
 import org.springframework.ai.tool.ToolCallback;
 import org.springframework.ai.tool.definition.ToolDefinition;
 import org.springframework.ai.tool.execution.ToolExecutionException;
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
 import org.springframework.util.StringUtils;
 
 /**

mcp/common/src/main/java/org/springframework/ai/mcp/McpToolUtils.java

@@ -42,7 +42,7 @@
 import org.springframework.ai.tool.definition.DefaultToolDefinition;
 import org.springframework.ai.tool.definition.ToolDefinition;
 import org.springframework.ai.util.json.schema.JsonSchemaUtils;
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
 import org.springframework.util.CollectionUtils;
 import org.springframework.util.MimeType;
 

mcp/common/src/main/java/org/springframework/ai/mcp/SyncMcpToolCallback.java

@@ -31,7 +31,7 @@
 import org.springframework.ai.tool.ToolCallback;
 import org.springframework.ai.tool.definition.ToolDefinition;
 import org.springframework.ai.tool.execution.ToolExecutionException;
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
 import org.springframework.util.StringUtils;
 
 /**

mcp/common/src/main/java/org/springframework/ai/mcp/aot/McpHints.java

@@ -25,7 +25,7 @@
 import org.springframework.aot.hint.RuntimeHints;
 import org.springframework.aot.hint.RuntimeHintsRegistrar;
 import org.springframework.aot.hint.TypeReference;
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
 
 /**
  * Runtime hints registrar for Model Context Protocol (MCP) schema classes.

memory/repository/spring-ai-model-chat-memory-repository-jdbc/src/main/java/org/springframework/ai/chat/memory/repository/jdbc/JdbcChatMemoryRepository.java

@@ -40,7 +40,7 @@
 import org.springframework.jdbc.core.JdbcTemplate;
 import org.springframework.jdbc.core.RowMapper;
 import org.springframework.jdbc.datasource.DataSourceTransactionManager;
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
 import org.springframework.transaction.PlatformTransactionManager;
 import org.springframework.transaction.support.TransactionTemplate;
 import org.springframework.util.Assert;

models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/AnthropicChatOptions.java

@@ -39,7 +39,7 @@
 import org.springframework.ai.model.tool.StructuredOutputChatOptions;
 import org.springframework.ai.model.tool.ToolCallingChatOptions;
 import org.springframework.ai.tool.ToolCallback;
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
 import org.springframework.util.Assert;
 
 /**
@@ -652,4 +652,4 @@ public AnthropicChatOptions build() {
 
 	}
 
-}
+}

models/spring-ai-anthropic/src/main/java/org/springframework/ai/anthropic/aot/AnthropicRuntimeHints.java

@@ -20,7 +20,7 @@
 import org.springframework.aot.hint.RuntimeHints;
 import org.springframework.aot.hint.RuntimeHintsRegistrar;
 import org.springframework.lang.NonNull;
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
 
 import static org.springframework.ai.aot.AiRuntimeHints.findJsonAnnotatedClassesInPackage;
 

models/spring-ai-azure-openai/src/main/java/org/springframework/ai/azure/openai/AzureOpenAiChatOptions.java

@@ -36,7 +36,7 @@
 
 import org.springframework.ai.model.tool.ToolCallingChatOptions;
 import org.springframework.ai.tool.ToolCallback;
-import org.springframework.lang.Nullable;
+import org.jspecify.annotations.Nullable;
 import org.springframework.util.Assert;
 
 /**