[DrJava] OutOfMemory error when compiling code with undeclared variables

[Merrill, A. <Mer...@ca...>]

Background:  As you may know, there is a bug in javac (not DrJava) that
results in the compiler throwing an OutOfMemoryError when compiling even
very short files that contain undeclared variables.  For example, try to
compile:
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class BugClass
{
  void method1()
  {
               x =3D a + b;
              }
}
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If you compile this using javac (not DrJava), you see the following
messages:
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C:\Documents\Java>javac BugClass.java
BugClass.java:5: cannot resolve symbol
symbol  : variable x
location: class BugClass
    x =3D a + b;
    ^
BugClass.java:5: cannot resolve symbol
symbol  : variable a
location: class BugClass
    x =3D a + b;
        ^
BugClass.java:5: cannot resolve symbol
symbol  : variable b
location: class BugClass
    x =3D a + b;
                       ^
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The system is out of resources.
Consult the following stack trace for details.
java.lang.OutOfMemoryError
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However, if you try to compile this in DrJava, the only error you see
is:
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1 error found:
File: (no associated file)  [line: (no source location)]
Error: Compile exception: java.lang.OutOfMemoryError
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Notice that all of the "cannot resolve symbol" errors are not displayed!
In a long program, this makes it very difficult to find the real problem
- all you know is that there is an undeclared variable somewhere in
perhaps thousands of lines of code. =20
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DrJava should display all of the output from the java compiler, even if
the java compiler crashes while trying to compile a program.  I use
DrJava in the high school classes that I teach, and students frequently
use variables they forget to declare. =20
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Andrew Merrill
Computer Science
Catlin Gabel School
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