Use StackWalker to deduce main application class

See gh-31701

Author: GGGGGHT

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/SpringApplication.java

@@ -25,6 +25,7 @@
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Properties;
 import java.util.Set;
 import java.util.stream.Collectors;
@@ -274,18 +275,10 @@ public SpringApplication(ResourceLoader resourceLoader, Class<?>... primarySourc
 	}
 
 	private Class<?> deduceMainApplicationClass() {
-		try {
-			StackTraceElement[] stackTrace = new RuntimeException().getStackTrace();
-			for (StackTraceElement stackTraceElement : stackTrace) {
-				if ("main".equals(stackTraceElement.getMethodName())) {
-					return Class.forName(stackTraceElement.getClassName());
-				}
-			}
-		}
-		catch (ClassNotFoundException ex) {
-			// Swallow and continue
-		}
-		return null;
+		return StackWalker.getInstance(StackWalker.Option.RETAIN_CLASS_REFERENCE)
+				.walk((s) -> s.filter(e -> Objects.equals(e.getMethodName(), "main")).findFirst()
+						.map(StackWalker.StackFrame::getDeclaringClass))
+				.orElse(null);
 	}
 
 	/**

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/SpringApplicationTests.java

@@ -23,6 +23,7 @@
 import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.Set;
 import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
@@ -1314,6 +1315,35 @@ void shouldRegisterHints() {
 						.accepts(hints);
 	}
 
+	@Test
+	void deduceMainApplicationClass() {
+		assertThat(
+				Objects.equals(deduceMainApplicationClassByStackWalker(), deduceMainApplicationClassByThrowException()))
+						.isTrue();
+	}
+
+	private Class<?> deduceMainApplicationClassByThrowException() {
+		try {
+			StackTraceElement[] stackTrace = new RuntimeException().getStackTrace();
+			for (StackTraceElement stackTraceElement : stackTrace) {
+				if ("main".equals(stackTraceElement.getMethodName())) {
+					return Class.forName(stackTraceElement.getClassName());
+				}
+			}
+		}
+		catch (ClassNotFoundException ex) {
+			// Swallow and continue
+		}
+		return null;
+	}
+
+	private Class<?> deduceMainApplicationClassByStackWalker() {
+		return StackWalker.getInstance(StackWalker.Option.RETAIN_CLASS_REFERENCE)
+				.walk((s) -> s.filter(e -> Objects.equals(e.getMethodName(), "main")).findFirst()
+						.map(StackWalker.StackFrame::getDeclaringClass))
+				.orElse(null);
+	}
+
 	private <S extends AvailabilityState> ArgumentMatcher<ApplicationEvent> isAvailabilityChangeEventWithState(
 			S state) {
 		return (argument) -> (argument instanceof AvailabilityChangeEvent<?>)