Add a warning about fully executable archive

Closes gh-9574

spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/RepackageMojo.java

@@ -152,6 +152,12 @@ public class RepackageMojo extends AbstractDependencyFilterMojo {
 	/**
 	 * Make a fully executable jar for *nix machines by prepending a launch script to the
 	 * jar.
+	 * <br/>
+	 * Currently, some tools do not accept this format so you may not always be able to
+	 * use this technique. For example, <code>jar -xf</code> may silently fail to extract
+	 * a jar or war that has been made fully-executable. It is recommended that you only
+	 * enable this option if you intend to execute it directly, rather than running it
+	 * with <code>java -jar</code> or deploying it to a servlet container.
 	 * @since 1.3
 	 */
 	@Parameter(defaultValue = "false")