Java’s Lineage
Java is related to C++, which is a direct descendent of C. Much of the character of Java
is inherited from these two languages. From C, Java derives its syntax. Many of Java’s
object-oriented features were influenced by C++. In fact, several of Java’s defining
characteristics come from—or are responses to—its predecessors. Moreover, the creation
of Java was deeply rooted in the process of refinement and adaptation that has been
occurring in computer programming languages for the past three decades. For these
reasons, this section reviews the sequence of events and forces that led up to Java. As
you will see, each innovation in language design was driven by the need to solve a
fundamental problem that the preceding languages could not solve. Java is no exception.
The Birth of Modern Programming: C
The C language shook the computer world. Its impact should not be underestimated,
because it fundamentally changed the way programming was approached and thought
about. The creation of C was a direct result of the need for a structured, efficient, highlevel
language that could replace assembly code when creating systems programs. As
you probably know, when a computer language is designed, trade-offs are often made,
such as the following:
■ Ease-of-use versus power
■ Safety versus efficiency
■ Rigidity versus extensibility
Prior to C, programmers usually had to choose between languages that optimized
one set of traits or the other. For example, although FORTRAN could be used to write
fairly efficient programs for scientific applications, it was not very good for systems
code. And while BASIC was easy to learn, it wasn’t very powerful, and its lack of
structure made its usefulness questionable for large programs. Assembly language
can be used to produce highly efficient programs, but it is not easy to learn or use
effectively. Further, debugging assembly code can be quite difficult.
Another compounding problem was that early computer languages such as BASIC,
COBOL, and FORTRAN were not designed around structured principles. Instead, they
relied upon the GOTO as a primary means of program control. As a result, programs
written using these languages tended to produce “spaghetti code”—a mass of tangled
jumps and conditional branches that make a program virtually impossible to
understand. While languages like Pascal are structured, they were not designed for
efficiency, and failed to include certain features necessary to make them applicable to
a wide range of programs. (Specifically, given the standard dialects of Pascal available
at the time, it was not practical to consider using Pascal for systems-level code.)
So, just prior to the invention of C, no one language had reconciled the conflicting
attributes that had dogged earlier efforts. Yet the need for such a language was
pressing. By the early 1970s, the computer revolution was beginning to take hold, and
the demand for software was rapidly outpacing programmers’ ability to produce it.
A great deal of effort was being expended in academic circles in an attempt to create a
better computer language. But, and perhaps most importantly, a secondary force was
beginning to be felt. Computer hardware was finally becoming common enough that a
critical mass was being reached. No longer were computers kept behind locked doors.
For the first time, programmers were gaining virtually unlimited access to their
machines. This allowed the freedom to experiment. It also allowed programmers to
begin to create their own tools. On the eve of C’s creation, the stage was set for a
quantum leap forward in computer languages.
Invented and first implemented by Dennis Ritchie on a DEC PDP-11 running the
UNIX operating system, C was the result of a development process that started with
an older language called BCPL, developed by Martin Richards. BCPL influenced a
language called B, invented by Ken Thompson, which led to the development of C
in the 1970s. For many years, the de facto standard for C was the one supplied with
the UNIX operating system and described in The C Programming Language by Brian
Kernighan and Dennis Ritchie (Prentice-Hall, 1978). C was formally standardized in
December 1989, when the American National Standards Institute (ANSI) standard for
C was adopted.
The creation of C is considered by many to have marked the beginning of the
modern age of computer languages. It successfully synthesized the conflicting
attributes that had so troubled earlier languages. The result was a powerful, efficient,
structured language that was relatively easy to learn. It also included one other, nearly
intangible aspect: it was a programmer’s language. Prior to the invention of C, computer
languages were generally designed either as academic exercises or by bureaucratic
committees. C is different. It was designed, implemented, and developed by real,
The Genesis of Java 5
THE JAVA LANGUAGE
working programmers, reflecting the way that they approached the job of programming.
Its features were honed, tested, thought about, and rethought by the people who
actually used the language. The result was a language that programmers liked to use.
Indeed, C quickly attracted many followers who had a near-religious zeal for it. As
such, it found wide and rapid acceptance in the programmer community. In short,
C is a language designed by and for programmers. As you will see, Java has inherited
this legacy.
The Need for C++
During the late 1970s and early 1980s, C became the dominant computer programming
language, and it is still widely used today. Since C is a successful and useful language,
you might ask why a need for something else existed. The answer is complexity.
Throughout the history of programming, the increasing complexity of programs has
driven the need for better ways to manage that complexity. C++ is a response to that
need. To better understand why managing program complexity is fundamental to the
creation of C++, consider the following.
Approaches to programming have changed dramatically since the invention of the
computer. For example, when computers were first invented, programming was done
by manually toggling in the binary machine instructions by use of the front panel. As
long as programs were just a few hundred instructions long, this approach worked.
As programs grew, assembly language was invented so that a programmer could deal
with larger, increasingly complex programs by using symbolic representations of the
machine instructions. As programs continued to grow, high-level languages were
introduced that gave the programmer more tools with which to handle complexity.
The first widespread language was, of course, FORTRAN. While FORTRAN was
an impressive first step, it is hardly a language that encourages clear and easy-tounderstand
programs. The 1960s gave birth to structured programming. This is the
method of programming championed by languages such as C. The use of structured
languages enabled programmers to write, for the first time, moderately complex
programs fairly easily. However, even with structured programming methods, once a
project reaches a certain size, its complexity exceeds what a programmer can manage.
By the early 1980s, many projects were pushing the structured approach past its limits.
To solve this problem, a new way to program was invented, called object-oriented
programming (OOP). Object-oriented programming is discussed in detail later in this
book, but here is a brief definition: OOP is a programming methodology that helps
organize complex programs through the use of inheritance, encapsulation, and
polymorphism.
In the final analysis, although C is one of the world’s great programming languages,
there is a limit to its ability to handle complexity. Once a program exceeds somewhere
between 25,000 and 100,000 lines of code, it becomes so complex that it is difficult to
grasp as a totality. C++ allows this barrier to be broken, and helps the programmer
comprehend and manage larger programs.
THE JAVA LANGUAGE
C++ was invented by Bjarne Stroustrup in 1979, while he was working at Bell
Laboratories in Murray Hill, New Jersey. Stroustrup initially called the new language
“C with Classes.” However, in 1983, the name was changed to C++. C++ extends C
by adding object-oriented features. Because C++ is built upon the foundation of C,
it includes all of C’s features, attributes, and benefits. This is a crucial reason for the
success of C++ as a language. The invention of C++ was not an attempt to create a
completely new programming language. Instead, it was an enhancement to an already
highly successful one.
The Stage Is Set for Java
By the end of the 1980s and the early 1990s, object-oriented programming using C++
took hold. Indeed, for a brief moment it seemed as if programmers had finally found
the perfect language. Because C++ blended the high efficiency and stylistic elements of
C with the object-oriented paradigm, it was a language that could be used to create a
wide range of programs. However, just as in the past, forces were brewing that would,
once again, drive computer language evolution forward. Within a few years, the World
Wide Web and the Internet would reach critical mass. This event would precipitate
another revolution in programming.
The Creation of Java
Java was conceived by James Gosling, Patrick Naughton, Chris Warth, Ed Frank, and
Mike Sheridan at Sun Microsystems, Inc. in 1991. It took 18 months to develop the first
working version. This language was initially called “Oak” but was renamed “Java”
in 1995. Between the initial implementation of Oak in the fall of 1992 and the public
announcement of Java in the spring of 1995, many more people contributed to the design
and evolution of the language. Bill Joy, Arthur van Hoff, Jonathan Payne, Frank Yellin,
and Tim Lindholm were key contributors to the maturing of the original prototype.
Somewhat surprisingly, the original impetus for Java was not the Internet! Instead,
the primary motivation was the need for a platform-independent (that is, architectureneutral)
language that could be used to create software to be embedded in various
consumer electronic devices, such as microwave ovens and remote controls. As you
can probably guess, many different types of CPUs are used as controllers. The trouble
with C and C++ (and most other languages) is that they are designed to be compiled
for a specific target. Although it is possible to compile a C++ program for just about
any type of CPU, to do so requires a full C++ compiler targeted for that CPU. The
problem is that compilers are expensive and time-consuming to create. An easier—
and more cost-efficient—solution was needed. In an attempt to find such a solution,
Gosling and others began work on a portable, platform-independent language that
could be used to produce code that would run on a variety of CPUs under differing
environments. This effort ultimately led to the creation of Java
