From 23423b3572c3f14ee7d538ac76326aa462111856 Mon Sep 17 00:00:00 2001
From: Rohit Behera <126186063+r0h1tb@users.noreply.github.com>
Date: Sun, 2 Aug 2026 01:09:49 +0530
Subject: [PATCH] Skip gRPC port initializer when spring-grpc is absent

GrpcPortInfoApplicationContextInitializer is registered unconditionally via
META-INF/spring.factories, and its initialize() unconditionally adds a listener
declared as ApplicationListener<GrpcServerStartedEvent>.

When spring-boot-grpc-test is on the classpath but spring-grpc is not, Spring
resolves that listener's generic interface to decide whether to deliver an
event, and Class.getGenericInterfaces() throws:

  java.lang.TypeNotPresentException: Type
  org.springframework.grpc.server.lifecycle.GrpcServerStartedEvent not present
    at java.base/java.lang.Class.getGenericInterfaces(Class.java:1278)
    at org.springframework.core.ResolvableType.getInterfaces(ResolvableType.java:544)

Guard registration on the event type being present, using ClassUtils.isPresent
as LogbackLoggingSystem already does for the SLF4J bridge handler.

See gh-50825
---
 ...PortInfoApplicationContextInitializer.java |  6 +++++
 ...nfoApplicationContextInitializerTests.java | 26 +++++++++++++++++++
 2 files changed, 32 insertions(+)

diff --git a/module/spring-boot-grpc-test/src/main/java/org/springframework/boot/grpc/test/autoconfigure/GrpcPortInfoApplicationContextInitializer.java b/module/spring-boot-grpc-test/src/main/java/org/springframework/boot/grpc/test/autoconfigure/GrpcPortInfoApplicationContextInitializer.java
index 76f1e0a30673..5d8a7c726423 100644
--- a/module/spring-boot-grpc-test/src/main/java/org/springframework/boot/grpc/test/autoconfigure/GrpcPortInfoApplicationContextInitializer.java
+++ b/module/spring-boot-grpc-test/src/main/java/org/springframework/boot/grpc/test/autoconfigure/GrpcPortInfoApplicationContextInitializer.java
@@ -31,6 +31,7 @@
 import org.springframework.core.env.MapPropertySource;
 import org.springframework.core.env.MutablePropertySources;
 import org.springframework.core.env.PropertySource;
+import org.springframework.util.ClassUtils;
 import org.springframework.grpc.server.GrpcServerFactory;
 import org.springframework.grpc.server.InProcessGrpcServerFactory;
 import org.springframework.grpc.server.lifecycle.GrpcServerStartedEvent;
@@ -50,8 +51,13 @@
 class GrpcPortInfoApplicationContextInitializer
 		implements ApplicationContextInitializer<ConfigurableApplicationContext> {
 
+	private static final String GRPC_SERVER_STARTED_EVENT = "org.springframework.grpc.server.lifecycle.GrpcServerStartedEvent";
+
 	@Override
 	public void initialize(ConfigurableApplicationContext applicationContext) {
+		if (!ClassUtils.isPresent(GRPC_SERVER_STARTED_EVENT, applicationContext.getClassLoader())) {
+			return;
+		}
 		applicationContext.addApplicationListener(new Listener(applicationContext));
 	}
 
diff --git a/module/spring-boot-grpc-test/src/test/java/org/springframework/boot/grpc/test/autoconfigure/GrpcPortInfoApplicationContextInitializerTests.java b/module/spring-boot-grpc-test/src/test/java/org/springframework/boot/grpc/test/autoconfigure/GrpcPortInfoApplicationContextInitializerTests.java
index 7e37a43647cd..b76df6a9ca01 100644
--- a/module/spring-boot-grpc-test/src/test/java/org/springframework/boot/grpc/test/autoconfigure/GrpcPortInfoApplicationContextInitializerTests.java
+++ b/module/spring-boot-grpc-test/src/test/java/org/springframework/boot/grpc/test/autoconfigure/GrpcPortInfoApplicationContextInitializerTests.java
@@ -16,10 +16,13 @@
 
 package org.springframework.boot.grpc.test.autoconfigure;
 
+import java.io.IOException;
+
 import io.grpc.Server;
 import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.Test;
 
+import org.springframework.boot.test.context.FilteredClassLoader;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
@@ -43,6 +46,29 @@ class GrpcPortInfoApplicationContextInitializerTests {
 
 	private static final String PORT_PROPERTY = "local.grpc.server.port";
 
+	@Test
+	void whenGrpcServerStartedEventIsNotOnTheClasspathRegistersNoListener() throws IOException {
+		// gh-50825: the initializer is registered unconditionally via
+		// spring.factories, so with spring-grpc absent the listener's generic
+		// interface cannot be resolved and Spring throws TypeNotPresentException.
+		try (AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext();
+				FilteredClassLoader classLoader = new FilteredClassLoader(GrpcServerStartedEvent.class)) {
+			context.setClassLoader(classLoader);
+			int before = context.getApplicationListeners().size();
+			new GrpcPortInfoApplicationContextInitializer().initialize(context);
+			assertThat(context.getApplicationListeners()).hasSize(before);
+		}
+	}
+
+	@Test
+	void whenGrpcServerStartedEventIsOnTheClasspathRegistersListener() {
+		try (AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext()) {
+			int before = context.getApplicationListeners().size();
+			new GrpcPortInfoApplicationContextInitializer().initialize(context);
+			assertThat(context.getApplicationListeners()).hasSize(before + 1);
+		}
+	}
+
 	@Test
 	void whenServerHasAddressInitializerSetsPortProperty() {
 		NettyGrpcServerFactory factory = mock();