[Demonstration 1]

[Buggy Method]
private void showReturnBookList() {
    System.out.println("Here is the book list:");
    System.out.println("---------------------------------------------");
    System.out.printf("%-5s", "Id");
    System.out.printf("%-20s", "Name");
    System.out.printf("%-20s", "Author");
    System.out.printf("%-20s", "Year");
    System.out.printf("\n");
    System.out.println("---------------------------------------------");
    for (Book book : bookList) {
        if (book.getBookState().equals(BookState.CHECKED_OUT)) {
            System.out.printf("%-5s", book.getBookId());
            System.out.printf("%-20s", book.getBookName());
            System.out.printf("%-20s", book.getBookAuthor());
            System.out.printf("%-20s", book.getPublishedYear());
            System.out.println();
            ;
        }
    }
    System.out.println("---------------------------------------------");
}

[Buggy Hunk]
for(Book book : bookList){

[Patch]
for(Book book : checkedOutBookList){

[Demonstration 2]

[Buggy Method]
public static Result service(String ownerName, String projectName, String service, boolean isAdvertise) throws IOException, UnsupportedOperationException, ServletException {
    if (!isSupportedService(service)) {
        return forbidden(String.format("Unsupported service: '%s'", service));
    }
    Project project = Project.findByOwnerAndProjectName(ownerName, projectName);
    if (project == null) {
        return notFound();
    }
    models.User user = UserApp.currentUser();
    if (!isAllowed(project, service)) {
        if (user.isAnonymous()) {
            return BasicAuthAction.unauthorized(response());
        } else {
            // If you want the Git client showing your custom message to
            // the user, the Content-Type should be exact "text/plain"
            // without any parameter. For more details, see the code at
            // https://github.com/git/git/commit/426e70d4a11ce3b4f70636d57c6a0ab16ae08a00#diff-eea0ad565ec5903a11b6023755d491cfR154
            response().setHeader("Content-Type", "text/plain");
            return forbidden(String.format("'%s' has no permission to '%s/%s'.", user.name, ownerName, projectName));
        }
    }
    if (isAdvertise) {
        return ok(RepositoryService.gitAdvertise(project, service, response()));
    } else {
        if (request().body().isMaxSizeExceeded()) {
            return status(REQUEST_ENTITY_TOO_LARGE);
        } else {
            user.visits(project);
            return ok(RepositoryService.gitRpc(project, service, request(), response()));
        }
    }
}

[Buggy Hunk]
user.name, ownerName, projectName));

[Patch]
user.loginId, ownerName, projectName));

[Demonstration 3]

[Buggy Method]
public void test() {
    System.out.printf("test");
}

[Buggy Hunk]
System.out.printf("test");

[Patch]
System.out.println("test");