diff --git a/makefile b/makefile
index 59099aa323..f9762c6938 100644
--- a/makefile
+++ b/makefile
@@ -43,6 +43,10 @@ endif
 ifeq ($(continuations),true)
 	options := $(options)-continuations
 endif
+ifdef gnu
+  options := $(options)-gnu
+	gnu-sources = $(src)/gnu.cpp
+endif
 
 root = $(shell (cd .. && pwd))
 build = build
@@ -232,7 +236,8 @@ vm-sources = \
 	$(src)/$(process).cpp \
 	$(src)/builtin.cpp \
 	$(src)/jnienv.cpp \
-	$(src)/process.cpp
+	$(src)/process.cpp \
+	$(gnu-sources)
 
 vm-asm-sources = $(src)/$(asm).S
 
@@ -314,16 +319,38 @@ classpath-sources = $(shell find $(classpath) -name '*.java')
 classpath-classes = \
 	$(call java-classes,$(classpath-sources),$(classpath),$(classpath-build))
 classpath-object = $(native-build)/classpath-jar.o
-classpath-dep = $(classpath-build)/dep
+classpath-dep = $(classpath-build).dep
+
+gnu-blacklist = \
+	java/lang/AbstractStringBuffer.class \
+	java/lang/reflect/Proxy.class
+
+gnu-overrides = \
+	java/lang/Class.class \
+	java/lang/Enum.class \
+	java/lang/Object.class \
+	java/lang/StackTraceElement.class \
+	java/lang/String.class \
+	java/lang/StringBuffer.class \
+	java/lang/StringBuilder.class \
+	java/lang/Throwable.class \
+	java/lang/ref/PhantomReference.class \
+	java/lang/ref/Reference.class \
+	java/lang/ref/ReferenceQueue.class \
+	java/lang/ref/WeakReference.class \
+	java/lang/reflect/AccessibleObject.class \
+	java/lang/reflect/Constructor.class \
+	java/lang/reflect/Field.class \
+	java/lang/reflect/Method.class
 
 test-sources = $(wildcard $(test)/*.java)
 test-classes = $(call java-classes,$(test-sources),$(test),$(test-build))
-test-dep = $(test-build)/dep
+test-dep = $(test-build).dep
 
 test-extra-sources = $(wildcard $(test)/extra/*.java)
 test-extra-classes = \
 	$(call java-classes,$(test-extra-sources),$(test),$(test-build))
-test-extra-dep = $(test-build)/extra/dep
+test-extra-dep = $(test-build)-extra.dep
 
 class-name = $(patsubst $(1)/%.class,%,$(2))
 class-names = $(foreach x,$(2),$(call class-name,$(1),$(x)))
@@ -395,8 +422,8 @@ $(classpath-build)/%.class: $(classpath)/%.java
 
 $(classpath-dep): $(classpath-sources)
 	@echo "compiling classpath classes"
-	@mkdir -p $(dir $(@))
-	$(javac) -d $(dir $(@)) -bootclasspath $(classpath-build) \
+	@mkdir -p $(classpath-build)
+	$(javac) -d $(classpath-build) -bootclasspath $(classpath-build) \
 		$(shell $(MAKE) -s --no-print-directory $(classpath-classes))
 	@touch $(@)
 
@@ -405,8 +432,8 @@ $(test-build)/%.class: $(test)/%.java
 
 $(test-dep): $(test-sources)
 	@echo "compiling test classes"
-	@mkdir -p $(dir $(@))
-	$(javac) -d $(dir $(@)) -bootclasspath $(classpath-build) \
+	@mkdir -p $(test-build)
+	$(javac) -d $(test-build) -bootclasspath $(classpath-build) \
 		$(shell $(MAKE) -s --no-print-directory $(test-classes))
 	$(javac) -source 1.2 -target 1.1 -XDjsrlimit=0 -d $(dir $(@)) \
 		test/Subroutine.java
@@ -414,7 +441,7 @@ $(test-dep): $(test-sources)
 
 $(test-extra-dep): $(test-extra-sources)
 	@echo "compiling extra test classes"
-	@mkdir -p $(dir $(@))
+	@mkdir -p $(test-build)
 	$(javac) -d $(test-build) -bootclasspath $(classpath-build) \
 		$(shell $(MAKE) -s --no-print-directory $(test-extra-classes))
 	@touch $(@)
@@ -456,9 +483,21 @@ $(boot-object): $(boot-source)
 	$(compile-object)
 
 $(build)/classpath.jar: $(classpath-dep)
+ifdef gnu
+	mkdir $(build)/gnu
+	(wd=$$(pwd); \
+	 cd $(build)/gnu; \
+	 $(jar) xf $(gnu)/share/classpath/glibj.zip; \
+	 rm $(gnu-blacklist); \
+	 $(jar) c0f "$$($(native-path) "$${wd}/$(@)")" .)
 	(wd=$$(pwd); \
 	 cd $(classpath-build); \
-	 $(jar) c0f "$$($(native-path) "$${wd}/$(@)")" $$(find . -name '*.class'))
+	 $(jar) u0f "$$($(native-path) "$${wd}/$(@)")" $(gnu-overrides))
+else
+	(wd=$$(pwd); \
+	 cd $(classpath-build); \
+	 $(jar) c0f "$$($(native-path) "$${wd}/$(@)")" .)
+endif
 
 $(binaryToMacho): $(src)/binaryToMacho.cpp
 	$(cxx) $(^) -o $(@)
diff --git a/src/gnu.cpp b/src/gnu.cpp
new file mode 100644
index 0000000000..7620fe18bf
--- /dev/null
+++ b/src/gnu.cpp
@@ -0,0 +1,82 @@
+/* Copyright (c) 2009, Avian Contributors
+
+   Permission to use, copy, modify, and/or distribute this software
+   for any purpose with or without fee is hereby granted, provided
+   that the above copyright notice and this permission notice appear
+   in all copies.
+
+   There is NO WARRANTY for this software.  See license.txt for
+   details. */
+
+#include "machine.h"
+#include "constants.h"
+#include "processor.h"
+
+using namespace vm;
+
+namespace {
+
+void
+setProperty(Thread* t, object method, object properties,
+            const char* name, const void* value, const char* format = "%s")
+{
+  PROTECT(t, method);
+  PROTECT(t, properties);
+  
+  object n = makeString(t, "%s", name);
+  PROTECT(t, n);
+
+  object v = makeString(t, format, value);
+
+  t->m->processor->invoke(t, method, properties, n, v);
+}
+
+} // namespace
+
+extern "C" JNIEXPORT void JNICALL
+Avian_gnu_classpath_VMSystemProperties_preInit
+(Thread* t, object, uintptr_t* arguments)
+{
+  object properties = reinterpret_cast<object>(arguments[0]);
+  PROTECT(t, properties);
+
+  object method = resolveMethod
+    (t, "java/util/Properties", "setProperty",
+     "(Ljava/lang/String;Ljava/lang/String;)Ljava/lang/Object;");
+
+  if (UNLIKELY(t->exception)) {
+    return;
+  }
+
+  PROTECT(t, method);
+
+  setProperty(t, method, properties, "java.vm.name", "Avian");
+
+  setProperty(t, method, properties, "java.lang.classpath",
+              t->m->finder->path());
+
+  setProperty(t, method, properties, "file.encoding", "ASCII");
+
+#ifdef WIN32 
+  setProperty(t, method, properties, "line.separator", "\r\n");
+  setProperty(t, method, properties, "file.separator", "\\");
+  setProperty(t, method, properties, "os.name", "Windows");
+
+  TCHAR buffer[MAX_PATH];
+  GetTempPath(MAX_PATH, buffer);
+  setProperty(t, method, properties, "java.io.tmpdir", buffer);
+
+  LPWSTR home = _wgetenv(L"USERPROFILE");
+  setProperty(t, method, properties, "user.home", home, "%ls");
+#else
+  setProperty(t, method, properties, "line.separator", "\n");
+  setProperty(t, method, properties, "file.separator", "/");
+#  ifdef __APPLE__
+  setProperty(t, method, properties, "os.name", "Mac OS X");
+#  else
+  setProperty(t, method, properties, "os.name", "Linux");
+#  endif
+  setProperty(t, method, properties, "java.io.tmpdir", "/tmp");
+  setProperty(t, method, properties, "user.home", getenv("HOME"));
+#endif
+}