Polish "Use try-with-resources to close resources automatically"

- Apply code formatting
- Use try-with-resources in many other places that were missed in the
  pull request

Closes gh-8045

spring-boot-tools/spring-boot-test-support/src/main/java/org/springframework/boot/junit/runner/classpath/ModifiedClassPathRunner.java

@@ -125,14 +125,10 @@ public class ModifiedClassPathRunner extends BlockJUnit4ClassRunner {
 	}
 
 	private String[] getClassPath(URL booterJar) throws Exception {
-		JarFile jarFile = new JarFile(new File(booterJar.toURI()));
-		try {
+		try (JarFile jarFile = new JarFile(new File(booterJar.toURI()))) {
 			return StringUtils.delimitedListToStringArray(jarFile.getManifest()
 					.getMainAttributes().getValue(Attributes.Name.CLASS_PATH), " ");
 		}
-		finally {
-			jarFile.close();
-		}
 	}
 
 	private URL[] processUrls(URL[] urls, Class<?> testClass) throws Exception {