diff --git a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/error/BasicErrorController.java b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/error/BasicErrorController.java
index dee8ab911b..0bd7571778 100644
--- a/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/error/BasicErrorController.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/web/servlet/error/BasicErrorController.java
@@ -33,7 +33,6 @@ import org.springframework.http.ResponseEntity;
 import org.springframework.stereotype.Controller;
 import org.springframework.util.Assert;
 import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.ResponseBody;
 import org.springframework.web.servlet.ModelAndView;
 
 /**
@@ -83,6 +82,16 @@ public class BasicErrorController extends AbstractErrorController {
 		return this.errorProperties.getPath();
 	}
 
+	@RequestMapping(produces = { "application/xml", "text/xml", "application/json",
+			"application/*+xml", "application/*+json" })
+	public ResponseEntity<Map<String, Object>> errorStructured(
+			HttpServletRequest request) {
+		Map<String, Object> body = getErrorAttributes(request,
+				isIncludeStackTrace(request, MediaType.ALL));
+		HttpStatus status = getStatus(request);
+		return new ResponseEntity<Map<String, Object>>(body, status);
+	}
+
 	@RequestMapping(produces = "text/html")
 	public ModelAndView errorHtml(HttpServletRequest request,
 			HttpServletResponse response) {
@@ -95,12 +104,20 @@ public class BasicErrorController extends AbstractErrorController {
 	}
 
 	@RequestMapping
-	@ResponseBody
-	public ResponseEntity<Map<String, Object>> error(HttpServletRequest request) {
-		Map<String, Object> body = getErrorAttributes(request,
-				isIncludeStackTrace(request, MediaType.ALL));
+	public ResponseEntity<String> errorText(HttpServletRequest request) {
+		Map<String, Object> attributes = getErrorAttributes(request,
+				isIncludeStackTrace(request, MediaType.TEXT_PLAIN));
+		int padding = 0;
+		for (Map.Entry<String, Object> entry : attributes.entrySet()) {
+			padding = Math.max(padding, entry.getKey().length());
+		}
+		StringBuffer body = new StringBuffer();
+		for (Map.Entry<String, Object> entry : attributes.entrySet()) {
+			body.append(String.format("%-" + padding + "s : %s%n", entry.getKey(),
+					entry.getValue()));
+		}
 		HttpStatus status = getStatus(request);
-		return new ResponseEntity<>(body, status);
+		return new ResponseEntity<>(body.toString(), status);
 	}
 
 	/**
diff --git a/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/servlet/error/BasicErrorControllerIntegrationTests.java b/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/servlet/error/BasicErrorControllerIntegrationTests.java
index 6b32f333c8..1af5e07cce 100755
--- a/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/servlet/error/BasicErrorControllerIntegrationTests.java
+++ b/spring-boot-project/spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/web/servlet/error/BasicErrorControllerIntegrationTests.java
@@ -169,6 +169,7 @@ public class BasicErrorControllerIntegrationTests {
 		load("--server.error.include-exception=true");
 		RequestEntity request = RequestEntity
 				.post(URI.create(createUrl("/bodyValidation")))
+				.accept(MediaType.APPLICATION_JSON)
 				.contentType(MediaType.APPLICATION_JSON).body("{}");
 		ResponseEntity<Map> entity = new TestRestTemplate().exchange(request, Map.class);
 		String resp = entity.getBody().toString();
@@ -189,6 +190,18 @@ public class BasicErrorControllerIntegrationTests {
 		assertThat(resp).doesNotContain("org.springframework.validation.BindException");
 	}
 
+	@Test
+	public void testRequestBodyValidationForText() {
+		load();
+		RequestEntity<Void> request = RequestEntity.post(URI.create(createUrl("/")))
+				.accept(MediaType.TEXT_PLAIN).build();
+		ResponseEntity<String> entity = new TestRestTemplate().exchange(request,
+				String.class);
+		String resp = entity.getBody().toString();
+		assertThat(resp).contains("status");
+		assertThat(resp).contains("error");
+	}
+
 	@Test
 	public void testConventionTemplateMapping() {
 		load();
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/Handler.java b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/Handler.java
index c09cd8b13f..f3b36f6111 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/Handler.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/main/java/org/springframework/boot/loader/jar/Handler.java
@@ -92,7 +92,8 @@ public class Handler extends URLStreamHandler {
 
 	@Override
 	protected URLConnection openConnection(URL url) throws IOException {
-		if (this.jarFile != null) {
+		if (this.jarFile != null
+				&& url.toString().startsWith(this.jarFile.getUrl().toString())) {
 			return JarURLConnection.get(url, this.jarFile);
 		}
 		try {
diff --git a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileTests.java b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileTests.java
index 0f1af0aac9..c00f2f16fb 100644
--- a/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileTests.java
+++ b/spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarFileTests.java
@@ -481,4 +481,24 @@ public class JarFileTests {
 		assertThat(temp.delete()).isTrue();
 	}
 
+	@Test
+	public void createUrlFromStringWithContextWhenNotFound() throws Exception {
+		// gh-12483
+		JarURLConnection.setUseFastExceptions(true);
+		try {
+			JarFile.registerUrlProtocolHandler();
+			JarFile nested = this.jarFile
+					.getNestedJarFile(this.jarFile.getEntry("nested.jar"));
+			URL context = nested.getUrl();
+			new URL(context, "jar:" + this.rootJarFile.toURI() + "!/nested.jar!/3.dat")
+					.openConnection().getInputStream().close();
+			this.thrown.expect(FileNotFoundException.class);
+			new URL(context, "jar:" + this.rootJarFile.toURI() + "!/no.dat")
+					.openConnection().getInputStream().close();
+		}
+		finally {
+			JarURLConnection.setUseFastExceptions(false);
+		}
+	}
+
 }