Tracing the Lineage: How Java Owes a Debt to Smalltalk

Introduction

In the vast landscape of programming languages, it is crucial to recognize the historical influences that shape the tools we use today. It is unquestionable that Java, one of the most widely deployed programming language and technology, owes a significant debt to Smalltalk, a pioneering visual environment in the realm of object-oriented programming (OOP). It is surprising how often this connection is overlooked by us, Java developers. My aim is to shed some light on the debt Java owes to Smalltalk, particularly in terms of its terminology and concepts. En passant, I will touch on the fascinating link between Smalltalk's object-oriented concepts and the field of cell biology, as envisioned by its visionary creator, Alan Kay.

Smalltalk: A Revolution in Object-Oriented Programming

In Smalltalk, conceived by Alan Kay and his team at Xerox PARC in the 1970s, the central premise was the concept of objects and message passing as the foundation of computation: everything is an object, and communication between objects occurs through message passing. These ideas were groundbreaking and paved the way for future object-oriented languages, including Java.

Java's Indebtedness to Smalltalk

When Java was developed by James Gosling and his team at Sun Microsystems in the mid-1990s, it drew inspiration from various programming languages, including Smalltalk. Java adopted several key concepts from Smalltalk, subtly but significantly shaping its design and terminology. Some of these aspects are:

1. Object-Orientation: Smalltalk introduced the world to true object-orientation, and Java inherited this core principle. In both languages, objects encapsulate state and behavior, promoting modularity and reusability. The object-oriented paradigm has become foundational in contemporary software development since then.
2. Message Passing: the concept of message passing, pioneered in Smalltalk, profoundly influenced Java's method invocation model. Java methods resemble Smalltalk messages, with objects communicating by invoking methods on one another. This elegant mechanism enables dynamic dispatch and runtime polymorphism, vital features of both languages.
3. Classes and Inheritance: Smalltalk's notion of classes and inheritance directly influenced Java's class-based object model and interface subtyping. Both languages employ classes as blueprints for objects, facilitating code organization and reuse. Inheritance, the ontological dual, allows the creation of hierarchical relationships between classes and interfaces in Java.
4. Garbage Collection: Smalltalk, predated by Lisp by the way, was an early adopter of garbage collection, a technique that simplifies memory management. Java inherited and further excelled in this feature, making memory allocation and deallocation automatic and relieving developers from manual memory management tasks.

The Biological Inspiration

One fascinating aspect of Smalltalk's origins is its connection to the field of cell biology. Alan Kay, a proponent of interdisciplinary thinking, drew inspiration from the biological domain when conceiving Smalltalk's object-oriented concepts: the idea of cells communicating via sending and receiving signals inspired the communication mechanisms in Smalltalk. In my opinion, this is one of the finest examples of nature-inspired computation.

Acknowledging the Debt

It is essential to recognize the debt Java owes to Smalltalk, as it allows us to appreciate the historical context and evolutionary path of programming languages. Java's success can be partially attributed to the solid foundation laid by Smalltalk's innovative ideas. Developers, especially those well-versed in Java, should acknowledge and embrace this historical connection, amplifying the understanding of their tools and encouraging the exploration of alternative paradigms.

Conclusion

It has always been striking to me how Java owes a significant debt to Smalltalk. Examining the historical lineage and exploring the conceptual link between Smalltalk's object-oriented ideas and cell biology, is crucial for understanding the foundations of the programming languages we use today and appreciating the rich history behind their design choices. Let us acknowledge the debt to Smalltalk and embrace the heritage that has shaped our contemporary programming practices.

Bibliographic References

Ingalls, D. (2020). The Evolution of Smalltalk: From Smalltalk-72 through Squeak. Proceedings of the ACM on Programming Languages, 4(HOPL)

Kay, Alan. (1993). The Early History of Smalltalk. ACM SIGPLAN Notices, Volume 28, Issue 3