diff --git a/src/main/java/net/lamgc/oracle/sentry/ApplicationMain.java b/src/main/java/net/lamgc/oracle/sentry/ApplicationMain.java
index 408a651..f6ad9e8 100644
--- a/src/main/java/net/lamgc/oracle/sentry/ApplicationMain.java
+++ b/src/main/java/net/lamgc/oracle/sentry/ApplicationMain.java
@@ -12,7 +12,7 @@ import org.springframework.context.annotation.Configuration;
  */
 @SpringBootApplication
 @Configuration
-public class ApplicationMain {
+class ApplicationMain {
 
     private final static Logger log = LoggerFactory.getLogger(ApplicationMain.class);
 
diff --git a/src/main/java/net/lamgc/oracle/sentry/ComputeInstanceManager.java b/src/main/java/net/lamgc/oracle/sentry/ComputeInstanceManager.java
index c6596b3..402fe33 100644
--- a/src/main/java/net/lamgc/oracle/sentry/ComputeInstanceManager.java
+++ b/src/main/java/net/lamgc/oracle/sentry/ComputeInstanceManager.java
@@ -22,7 +22,7 @@ import java.util.stream.Collectors;
  * 计算实例管理器.
  * @author LamGC
  */
-public class ComputeInstanceManager {
+public final class ComputeInstanceManager {
 
     private final Map<String, ComputeInstance> instanceMap = new ConcurrentHashMap<>();
     private SshAuthIdentityProvider sshIdentityProvider;