Perform failure analysis of NoSuchMethodErrors

Closes gh-14040

Author: wilkinsona

spring-boot/src/main/java/org/springframework/boot/diagnostics/analyzer/NoSuchMethodFailureAnalyzer.java

@@ -0,0 +1,108 @@
+/*
+ * Copyright 2012-2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.diagnostics.analyzer;
+
+import java.io.PrintWriter;
+import java.io.StringWriter;
+import java.net.URL;
+import java.util.Collections;
+import java.util.List;
+
+import org.springframework.boot.diagnostics.AbstractFailureAnalyzer;
+import org.springframework.boot.diagnostics.FailureAnalysis;
+import org.springframework.util.ClassUtils;
+
+/**
+ * An {@link AbstractFailureAnalyzer} that analyzes {@link NoSuchMethodError
+ * NoSuchMethodErrors}.
+ *
+ * @author Andy Wilkinson
+ */
+class NoSuchMethodFailureAnalyzer extends AbstractFailureAnalyzer<NoSuchMethodError> {
+
+	@Override
+	protected FailureAnalysis analyze(Throwable rootFailure, NoSuchMethodError cause) {
+		String className = extractClassName(cause);
+		if (className == null) {
+			return null;
+		}
+		List<URL> candidates = findCandidates(className);
+		if (candidates == null) {
+			return null;
+		}
+		URL actual = getActual(className);
+		if (actual == null) {
+			return null;
+		}
+		StringWriter description = new StringWriter();
+		PrintWriter writer = new PrintWriter(description);
+		writer.print("An attempt was made to call the method ");
+		writer.print(cause.getMessage());
+		writer.print(" but it does not exist. Its class, ");
+		writer.print(className);
+		writer.println(", is available from the following locations:");
+		writer.println();
+		for (URL candidate : candidates) {
+			writer.print("    ");
+			writer.println(candidate);
+		}
+		writer.println();
+		writer.println("It was loaded from the following location:");
+		writer.println();
+		writer.print("    ");
+		writer.println(actual);
+		return new FailureAnalysis(description.toString(),
+				"Correct the classpath of your application so that it contains a single,"
+						+ " compatible version of " + className,
+				cause);
+	}
+
+	private String extractClassName(NoSuchMethodError cause) {
+		int descriptorIndex = cause.getMessage().indexOf('(');
+		if (descriptorIndex == -1) {
+			return null;
+		}
+		String classAndMethodName = cause.getMessage().substring(0, descriptorIndex);
+		int methodNameIndex = classAndMethodName.lastIndexOf('.');
+		if (methodNameIndex == -1) {
+			return null;
+		}
+		return classAndMethodName.substring(0, methodNameIndex);
+	}
+
+	private List<URL> findCandidates(String className) {
+		try {
+			return Collections.list((NoSuchMethodFailureAnalyzer.class.getClassLoader()
+					.getResources(ClassUtils.convertClassNameToResourcePath(className)
+							+ ".class")));
+		}
+		catch (Throwable ex) {
+			return null;
+		}
+	}
+
+	private URL getActual(String className) {
+		try {
+			return getClass().getClassLoader().loadClass(className).getProtectionDomain()
+					.getCodeSource().getLocation();
+		}
+		catch (Throwable ex) {
+			return null;
+		}
+	}
+
+}

spring-boot/src/main/resources/META-INF/spring.factories

@@ -37,6 +37,7 @@ org.springframework.boot.diagnostics.analyzer.BeanCurrentlyInCreationFailureAnal
 org.springframework.boot.diagnostics.analyzer.BeanNotOfRequiredTypeFailureAnalyzer,\
 org.springframework.boot.diagnostics.analyzer.BindFailureAnalyzer,\
 org.springframework.boot.diagnostics.analyzer.ConnectorStartFailureAnalyzer,\
+org.springframework.boot.diagnostics.analyzer.NoSuchMethodFailureAnalyzer,\
 org.springframework.boot.diagnostics.analyzer.NoUniqueBeanDefinitionFailureAnalyzer,\
 org.springframework.boot.diagnostics.analyzer.PortInUseFailureAnalyzer,\
 org.springframework.boot.diagnostics.analyzer.ValidationExceptionFailureAnalyzer

spring-boot/src/test/java/org/springframework/boot/diagnostics/analyzer/NoSuchMethodFailureAnalyzerTests.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright 2012-2018 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.diagnostics.analyzer;
+
+import javax.servlet.ServletContext;
+import javax.servlet.http.HttpServlet;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import org.springframework.boot.diagnostics.FailureAnalysis;
+import org.springframework.boot.junit.runner.classpath.ClassPathOverrides;
+import org.springframework.boot.junit.runner.classpath.ModifiedClassPathRunner;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+
+/**
+ * @author awilkinson
+ */
+@RunWith(ModifiedClassPathRunner.class)
+@ClassPathOverrides("javax.servlet:servlet-api:2.5")
+public class NoSuchMethodFailureAnalyzerTests {
+
+	@Test
+	public void noSuchMethodErrorIsAnalyzed() {
+		Throwable failure = createFailure();
+		assertThat(failure).isNotNull();
+		FailureAnalysis analysis = new NoSuchMethodFailureAnalyzer().analyze(failure);
+		assertThat(analysis).isNotNull();
+		assertThat(analysis.getDescription())
+				.contains("the method javax.servlet.ServletContext.addServlet"
+						+ "(Ljava/lang/String;Ljavax/servlet/Servlet;)"
+						+ "Ljavax/servlet/ServletRegistration$Dynamic;")
+				.contains("class, javax.servlet.ServletContext,");
+	}
+
+	private Throwable createFailure() {
+		try {
+			ServletContext servletContext = mock(ServletContext.class);
+			servletContext.addServlet("example", new HttpServlet() {
+			});
+			return null;
+		}
+		catch (Throwable ex) {
+			return ex;
+		}
+	}
+
+}