Polish "Log context path at startup"

Closes gh-10544

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/jetty/JettyWebServer.java

@@ -156,7 +156,7 @@ public class JettyWebServer implements WebServer {
 				this.started = true;
 				JettyWebServer.logger
 						.info("Jetty started on port(s) " + getActualPortsDescription()
-								+ " with context path " + getContextPath());
+								+ " with context path '" + getContextPath() + "'");
 			}
 			catch (WebServerException ex) {
 				throw ex;

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/tomcat/TomcatWebServer.java

@@ -195,7 +195,7 @@ public class TomcatWebServer implements WebServer {
 				this.started = true;
 				TomcatWebServer.logger
 						.info("Tomcat started on port(s): " + getPortsDescription(true)
-								+ " with context path " + getContextPath());
+								+ " with context path '" + getContextPath() + "'");
 			}
 			catch (ConnectorStartFailedException ex) {
 				stopSilently();

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/embedded/undertow/UndertowServletWebServer.java

@@ -158,7 +158,7 @@ public class UndertowServletWebServer implements WebServer {
 				this.started = true;
 				UndertowServletWebServer.logger
 						.info("Undertow started on port(s) " + getPortsDescription()
-								+ " with context path " + this.contextPath);
+								+ " with context path '" + this.contextPath + "'");
 			}
 			catch (Exception ex) {
 				try {

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/servlet/server/AbstractServletWebServerFactoryTests.java

@@ -263,6 +263,15 @@ public abstract class AbstractServletWebServerFactoryTests {
 		assertThat(getResponse(getLocalUrl("/say/hello"))).isEqualTo("Hello World");
 	}
 
+	@Test
+	public void contextPathIsLoggedOnStartup() {
+		AbstractServletWebServerFactory factory = getFactory();
+		factory.setContextPath("/custom");
+		this.webServer = factory.getWebServer(exampleServletRegistration());
+		this.webServer.start();
+		assertThat(this.output.toString()).containsOnlyOnce("with context path '/custom'");
+	}
+
 	@Test
 	public void contextPathMustStartWithSlash() throws Exception {
 		this.thrown.expect(IllegalArgumentException.class);