anchor.diff:  
   `@Command`-annotated classes that implement `Callable` and `@Command`-<<command-methods,annotated methods>> can simply return an `int` or `Integer`, and this value will be returned from `CommandLine.execute`. For example:
   
  -```java
  +.Java
  +[source,java,role="primary"]
  +----
   @Command(name = "greet")
   class Greet implements Callable<Integer> {
       public Integer call() {
  
positive.code: }
  ----
  
  Despite being only 15 lines long, this is a full-fledged application, with <<Mixin Standard Help Options,`--help` and `--version`>> options in addition to the `-x` option.
  The `execute` method will show the usage help or version information if requested by the user, and invalid user input will result
  in a helpful <<Handling Errors,error message>>. If the user input was valid, the business logic is invoked.
  
negative.code: 
  ==== Customizing Output Streams and ANSI settings
  
  Before:
  
  .Java
  [source,java,role="primary"]
  ----
  PrintStream out = // output stream for user-requested help
  PrintStream err = // output stream for error messages
  Ansi ansi = // to use ANSI colors and styles or not
  CommandLine.run(new MyRunnable(), out, err, ansi, args);
  ----
  
  .Kotlin
  [source,kotlin,role="secondary"]
  ----
  val out: PrintStream = // output stream for user-requested help
  val err: PrintStream = // output stream for error messages
  val ansi: Ansi = // to use ANSI colors and styles or not
  CommandLine.run(MyRunnable(), out, err, ansi, *args)
  ----
  
  After:
  
  .Java
  [source,java,role="primary"]
  ----
  PrintWriter out = // output stream for user-requested help
  PrintWriter err = // output stream for error messages
  Ansi ansi = // to use ANSI colors and styles or not
  