diff --git a/xds/src/main/java/io/grpc/xds/XdsServerBuilder.java b/xds/src/main/java/io/grpc/xds/XdsServerBuilder.java
index ba7e4490d66..d342e5e02ce 100644
--- a/xds/src/main/java/io/grpc/xds/XdsServerBuilder.java
+++ b/xds/src/main/java/io/grpc/xds/XdsServerBuilder.java
@@ -118,13 +118,21 @@ public XdsServerBuilder fallbackHandlerRegistry(@Nullable HandlerRegistry fallba
 
   @Override
   public XdsServerBuilder useTransportSecurity(File certChain, File privateKey) {
-    delegate.useTransportSecurity(certChain, privateKey);
+    try {
+      this.serverCredentials = TlsServerCredentials.create(certChain, privateKey);
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
     return this;
   }
 
   @Override
   public XdsServerBuilder useTransportSecurity(InputStream certChain, InputStream privateKey) {
-    delegate.useTransportSecurity(certChain, privateKey);
+    try {
+      this.serverCredentials = TlsServerCredentials.create(certChain, privateKey);
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
     return this;
   }
 
@@ -134,7 +142,7 @@ public XdsServerBuilder useTransportSecurity(InputStream certChain, InputStream
    */
   @ExperimentalApi("https://github.com/grpc/grpc-java/issues/7514")
   public XdsServerBuilder useXdsSecurityWithPlaintextFallback() {
-    this.serverCredentials = InsecureServerCredentials.create();
+    this.serverCredentials = XdsServerCredentials.create(InsecureServerCredentials.create());
     return this;
   }