chore: replace JDK 9+ API (List.of, Map.of) with JDK 8 equivalents, update java.version to 1.8, version to 2.3.x

Author: loong10k

pom.xml

@@ -6,7 +6,7 @@
 	<groupId>io.github.hiwepy</groupId>
 	<artifactId>opencode-java-sdk</artifactId>
 	<description>OpenCode Java SDK (HTTP Server + local CLI)</description>
-	<version>2.7.x.20260605-SNAPSHOT</version>
+	<version>2.3.x.20260605-SNAPSHOT</version>
 	<name>${project.groupId}:${project.artifactId}</name>
 	<url>https://github.com/hiwepy/${project.artifactId}</url>
 	<packaging>jar</packaging>
@@ -370,7 +370,7 @@
 
 	<properties>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-		<java.version>17</java.version>
+		<java.version>1.8</java.version>
 		<maven.version>3.0</maven.version>
 		<okhttp3.version>4.12.0</okhttp3.version>
 		<jackson.version>2.21.2</jackson.version>

src/main/java/io/github/hiwepy/opencode/api/OpenCodeHttpClient.java

@@ -12,6 +12,8 @@
 import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
+import java.util.Collections;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
@@ -64,7 +66,7 @@ public HealthStatus health() {
     // ============================================================
 
     public Session createSession(String title) {
-        Map<String, Object> body = title != null ? Map.of("title", title) : Map.of();
+        Map<String, Object> body = title != null ? Collections.singletonMap("title", title) : Collections.emptyMap();
         return post("/session", body, Session.class);
     }
 

src/main/java/io/github/hiwepy/opencode/api/model/ChatRequest.java

@@ -5,6 +5,7 @@
 import lombok.NoArgsConstructor;
 import lombok.Setter;
 
+import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 
@@ -58,7 +59,7 @@ public class ChatRequest {
     /** 快捷构造：单条 user 消息。 */
     public static ChatRequest ofUser(String content) {
         ChatRequest req = new ChatRequest();
-        req.setMessages(List.of(ChatMessage.user(content)));
+        req.setMessages(Collections.singletonList(ChatMessage.user(content)));
         return req;
     }
 

src/main/java/io/github/hiwepy/opencode/api/model/PromptRequest.java

@@ -5,6 +5,7 @@
 import lombok.Data;
 import lombok.NoArgsConstructor;
 
+import java.util.Collections;
 import java.util.List;
 
 /**
@@ -58,7 +59,7 @@ public static PromptRequest ofText(String text) {
         p.setType("text");
         p.setText(text);
         PromptRequest req = new PromptRequest();
-        req.setParts(List.of(p));
+        req.setParts(Collections.singletonList(p));
         return req;
     }