Michael Kölling

The BlueJ System and its Pedagogy

Many teachers experience serious problems when teaching object-orientation to beginners or professionals. Many of these problems could be overcome or reduced through the use of more appropriate tools. In this paper, we introduce BlueJ, an integrated development environment designed for teaching object-orientation, and discuss how the use of this tool can change the approach to teaching.

Guidelines for teaching object orientation with Java

How to best teach object orientation to first year students is currently a topic of much debate. One of the tools suggested to aid in this task is BlueJ, an integrated development environment specifically designed for teaching. BlueJ supports a unique style of introduction of OO concepts. In this paper we discuss a set of problems with OO teaching, present some guidelines for better course design and show how BlueJ can be used to make significant improvements to introductory OO courses. We end by presenting a description of a possible project sequence using this teaching approach.

Alice, Greenfoot, and Scratch -- A Discussion

This article distills a discussion about the goals, mechanisms, and effects of three environments which aim to support the acquisition and development of computing concepts (problem solving and programming) in pre-University and non-technical students: Alice, Greenfoot, and Scratch. The conversation started in a special session on the topic at the 2010 ACM SIGCSE Symposium on Computer Science Education and continued during the creation of the resulting Special Issue of the ACM Transactions on Computing Education.

An object-oriented program development environment for the first programming course

Over the last ten years there has been a major shift in programming language design from procedural languages to object-oriented languages. Most universities have adopted an object-oriented language for their first programming course. However, far less consideration has been given to the program development environment. In this paper we argue that the environment is possibly more important than the language and existing environments fail to fully support the object-oriented paradigm. We describe a new program development environment and show how it has been specifically designed to support object-oriented design and programming.

Blue—a language for teaching object-oriented programming

Teaching object-oriented programming has clearly become an important part of computer science education. We agree with many others that the best place to teach it is in the CS1 introductory course. Many problems with this have been reported in the literature. These mainly result from inadequate languages and environments. Blue is a new language and integrated programming environment, currently under development explicitly for object-oriented teaching. We expect clear advantages from the use of Blue for first year teaching compared to using other available languages. This paper describes the design principles on which the language was based and the most important aspects of the language itself.

Game programming in introductory courses with direct state manipulation

While the introduction of object-oriented programming slowly moves down the age groups - starting from advanced university courses, to introductory courses, and now into high schools - many attempts are being made to make object-oriented programming introduction less abstract and theoretical. Visualisation and interaction techniques are being applied in an attempt to give students engaging and concrete experiences with objects. Recently, the greenfoot environment has been proposed as another step in this development. In this paper, we describe new functionality in the greenfoot environment, especially the addition of user interaction programming via direct state manipulation. Direct state manipulation provides very low overhead graphical I/O handling at a level that makes it feasible to guide students to simple graphical game programming within a few weeks, while concentrating on fundamental object-oriented concepts in the structure of the program.

Bringing computer science back into schools: lessons from the UK

Computer science in UK schools is a subject in decline: the ratio of Computing to Maths A-Level students (i.e. ages 16--18) has fallen from 1:2 in 2003 to 1:20 in 2011 and in 2012. In 2011 and again in 2012, the ratio for female students was 1:100, with less than 300 female students taking Computing A-Level in the whole of the UK each year. Similar problems have been observed in the USA and other countries, despite the increased need for computer science skills caused by IT growth in industry and society. In the UK, the Computing At School (CAS) group was formed to try to improve the state of computer science in schools. Using a combination of grassroots teacher activities and policy lobbying at a national level, CAS has been able to rapidly gain traction in the fight for computer science in schools. We examine the reasons for this success, the challenges and dangers that lie ahead, and suggest how the experience of CAS in the UK can benefit other similar organisations, such as the CSTA in the USA.

Introducing unit testing with BlueJ

The teaching of testing has never been easy. The introduction of object orientation into first year courses has made it even more difficult, since more and smaller units need to be tested more often. In professional contexts this is addressed by the use of testing support software. Unfortunately, no adequate software to support testing for introductory students is widely available, leaving teachers and students of first year courses struggling.In this paper we describe an attempt to address this problem by combining two existing systems that partly address our needs. We describe an integration of JUnit into BlueJ, which creates a testing tool that exhibits the flexibility and ease-of-use of the BlueJ system combined with the structured unit test approach provided by JUnit.

Requirements for a first year object-oriented teaching language

Interest in teaching object-oriented programming in first year computer science courses has increased substantially over the last few years. While the theoretical advantages are clear, it is not obvious that the available object-oriented languages are suitable for this purpose. None of the existing languages is appropriate for teaching object-oriented principles. In this paper we discuss the requirements for an object-oriented teaching language and draw attention to the deficiencies of existing languages. In particular, the paper examines C++, Smalltalk, Eiffel and Sather. Finally we outline characteristics of a new language, specifically designed for teaching purposes.

Blackbox: a large scale repository of novice programmers' activity

Automatically observing and recording the programming behaviour of novices is an established computing education research technique. However, prior studies have been conducted at a single institution on a small or medium scale, without the possibility of data re-use. Now, the widespread availability of always-on Internet access allows for data collection at a much larger, global scale. In this paper we report on the Blackbox project, begun in June 2013. Blackbox is a perpetual data collection project that collects data from worldwide users of the BlueJ IDE -- a programming environment designed for novice programmers. Over one hundred thousand users have already opted-in to Blackbox. The collected data is anonymous and is available to other researchers for use in their own studies, thus benefitting the larger research community. In this paper, we describe the data available via Blackbox, show some examples of analyses that can be performed using the collected data, and discuss some of the analysis challenges that lie ahead.