Free but shackled: The Java trap

If your program is free software, it is basically ethical–but there is a trap you must be on guard for. Your program, though in itself free, may be restricted by non-free software that it depends on.
Since the problem is most prominent today for Java programs, we call
it the Java Trap.

A program is free software if its users have certain crucial freedoms.
Roughly speaking, they are: the freedom to run the program, the
freedom to study and change the source, the freedom to redistribute
the source and binaries, and the freedom to publish improved versions.
(See http://www.gnu.org/philosophy/free-sw.html.) Whether any given
program is free software depends solely on the meaning of its license.

Whether the program can be used in the Free World, used by people who
mean to live in freedom, is a more complex question. This is not
determined by the program’s own license, because no program works in
isolation. Every program depends on other programs. For instance, a
program needs to be compiled or interpreted, so it depends on a
compiler or interpreter. If compiled into byte code, it depends on a
byte code interpreter. Moreover, it needs libraries in order to run,
and it may also invoke other separate programs that run in other
processes. All of these programs are dependencies. Dependencies may
be necessary for the program to run at all, or they may be necessary
only for certain features. Either way, all or part of the program
cannot operate without the dependencies.

If some of a program’s dependencies are non-free, this means that all
or part of the program is unable to run in an entirely free system–it
is unusable in the Free World. Sure, we could redistribute the
program and have copies on our machines, but that’s not much good if
it won’t run. That program is free software, but it is effectively
shackled by its non-free dependencies.

This problem can occur in any kind of software, in any language. For
instance, a free program that only runs on Microsoft Windows is
clearly useless in the Free World. But software that runs on
GNU/Linux can also be useless if it depends on other non-free
software. In the past, Motif (before we had LessTif) and Qt (before
its developers made it free software) were major causes of this
problem. Most 3D video cards work fully only with non-free drivers,
which also cause this problem. But the major source of this problem
today is Java, because people who write free software often feel Java
is sexy. Blinded by their attraction to the language, they overlook
the issue of dependencies, and they fall into the Java Trap.

Sun’s implementation of Java is non-free. Blackdown is also non-free;
it is an adaptation of Sun’s proprietary code. The standard Java
libraries are non-free also. We do have free implementations of Java,
such as the GNU Java Compiler and GNU Classpath, but they don’t
support all the features yet. We are still catching up.

If you develop a Java program on Sun’s Java platform, you are liable
to use Sun-only features without even noticing. By the time you find
this out, you may have been using them for months, and redoing the
work could take more months. You might say, “It’s too much work to
start over.” Then your program will have fallen into the Java Trap;
it will be unusable in the Free World.

The reliable way to avoid the Java Trap is to have only a free
implementation of Java on your system. Then if you use a Java feature
or library that free software does not yet support, you will find out
straightaway, and you can rewrite that code immediately.

Sun continues to develop additional “standard” Java libraries, and
nearly all of them are non-free; in many cases, even library’s
specification is a trade secret, and Sun’s latest license for these
specifications prohibits release of anything less than a full
implementation of the specification. (See
http://jcp.org/aboutJava/communityprocess/JSPA2.pdf and
http://jcp.org/aboutJava/communityprocess/final/jsr129/j2me_pb-1_0-fr-spec-license.html,
for examples.

Fortunately, that specification license does permit releasing an
implementation as free software; others who receive the library can be
allowed to change it and are not required to adhere to the
specification. But the requirement has the effect of prohibiting the
use of a collaborative development model to produce the free
implementation. Use of that model would entail publishing incomplete
versions, which those who have read the spec are not allowed to do.

In the early days of the Free Software Movement, it was impossible to
avoid depending on non-free programs. Before we had the GNU C
compiler, every C program (free or not) depended on a non-free C
compiler. Before we had the GNU C library, every program depended on
a non-free C library. Before we had Linux, the first free kernel,
every program depended on a non-free kernel. Before we had Bash,
every shell script had to be interpreted by a non-free shell. It was
inevitable that our first programs would initially be hampered by
these dependencies, but we accepted this because our plan included
rescuing them subsequently. Our overall goal, a self-hosting GNU
operating system, included free replacements for all those
dependencies; if we reached the goal, all our programs would be
rescued. Thus it happened: with the GNU/Linux system, we can now run
these programs on free platforms.

The situation is different today. We now have powerful free operating
systems and many free programming tools. Whatever job you want to do,
you can do it on a free platform; there is no need to accept a
non-free dependency even temporarily. The main reason people fall
into the trap today is because they are not thinking about it. The
easiest solution to the problem of the Java Trap is to teach people
not to fall into it.

To keep your Java code safe from the Java Trap, install a free Java
development environment and use it. More generally, whatever language
you use, keep your eyes open, and check the free status of programs
your code depends on. The easiest way to verify that program is free
is by looking for it in the Free Software Directory
(http://www.fsf.org/directory). If a program is not in the directory,
you can check its license(s) against the list of free software
licenses (http://www.gnu.org/licenses/license-list.html).

We are trying to rescue the trapped Java programs, so if you like the
Java language, we invite you to help in developing GNU Classpath.
Trying your programs with the the GJC Compiler and GNU Classpath, and
reporting any problems you encounter in classes already implemented,
is also useful. However, finishing GNU Classpath will take time; if
more non-free libraries continue to be added, we may never have all
the latest ones. So please don’t put your free software in shackles.
When you write an application program today, write it to run on free
facilities from the start.

Copyright 2004 Richard Stallman
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