Polish Javadoc

Update Javadoc to add missing @return and @param elements.

spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/Layout.java

@@ -41,11 +41,13 @@ public interface Layout {
 
 	/**
 	 * Returns the location of classes within the archive.
+	 * @return the classes location
 	 */
 	String getClassesLocation();
 
 	/**
 	 * Returns if loader classes should be included to make the archive executable.
+	 * @return if the layout is executable
 	 */
 	boolean isExecutable();
 

spring-boot-tools/spring-boot-loader-tools/src/main/java/org/springframework/boot/loader/tools/MainClassFinder.java

@@ -192,6 +192,7 @@ public abstract class MainClassFinder {
 	 * Perform the given callback operation on all main classes from the given jar.
 	 * @param jarFile the jar file to search
 	 * @param classesLocation the location within the jar containing classes
+	 * @param callback the callback
 	 * @return the first callback result or {@code null}
 	 * @throws IOException
 	 */
@@ -310,6 +311,7 @@ public abstract class MainClassFinder {
 
 	/**
 	 * Callback interface used to receive class names.
+	 * @param <T> the result type
 	 */
 	public static interface ClassNameCallback<T> {