diff --git a/classpath/java/util/Hashtable.java b/classpath/java/util/Hashtable.java
index 2043fc0633..6bfd96b68d 100644
--- a/classpath/java/util/Hashtable.java
+++ b/classpath/java/util/Hashtable.java
@@ -11,6 +11,10 @@ public class Hashtable<K, V> implements Map<K, V> {
     this(0);
   }
 
+  public String toString() {
+    return map.toString();
+  }
+
   public synchronized int size() {
     return map.size();
   }
diff --git a/classpath/java/util/LinkedList.java b/classpath/java/util/LinkedList.java
index 5deae40931..3cfa4447e1 100644
--- a/classpath/java/util/LinkedList.java
+++ b/classpath/java/util/LinkedList.java
@@ -32,8 +32,8 @@ public class LinkedList<T> implements List<T> {
     if (front == null) {
       front = rear = c;
     } else {
-      c.prev = rear;
-      rear = c;
+      c.next = front;
+      front = c;
     }
   }
   
@@ -43,8 +43,8 @@ public class LinkedList<T> implements List<T> {
     if (front == null) {
       front = rear = c;
     } else {
-      c.next = front;
-      front = c;
+      c.prev = rear;
+      rear = c;
     }
   }
   
diff --git a/makefile b/makefile
index ff0ad44095..f4b84a877e 100644
--- a/makefile
+++ b/makefile
@@ -173,6 +173,14 @@ debug-jscheme: $(executable) $(input)
 vg-jscheme: $(executable) $(input)
 	LD_LIBRARY_PATH=$(bld) $(vg) $(<) -cp $(cls):$(jscheme) $(jscheme-command)
 
+.PHONY: profile-jscheme
+profile-jscheme: $(executable) $(input)
+	opcontrol --start; \
+	echo '(+ 5 6)' | LD_LIBRARY_PATH=$(bld) \
+		$(<) -cp $(cls):$(jscheme) jscheme/REPL; \
+	opcontrol --stop; \
+	opreport -l $(<)
+
 .PHONY: clean
 clean:
 	@echo "removing build"
diff --git a/src/builtin.cpp b/src/builtin.cpp
index 1f4cf5f0a6..4307107f15 100644
--- a/src/builtin.cpp
+++ b/src/builtin.cpp
@@ -16,10 +16,11 @@ replace(char a, char b, char* c)
 jstring
 Object_toString(Thread* t, jobject this_)
 {
+  unsigned hash = objectHash(t, *this_);
   object s = makeString
-    (t, "%s@%p",
+    (t, "%s@0x%x",
      &byteArrayBody(t, className(t, objectClass(t, *this_)), 0),
-     *this_);
+     hash);
 
   return pushReference(t, s);
 }
diff --git a/src/heap.cpp b/src/heap.cpp
index 35dab96254..9b0a8d95c5 100644
--- a/src/heap.cpp
+++ b/src/heap.cpp
@@ -744,7 +744,7 @@ bitsetSet(uintptr_t* p, unsigned i, bool v)
   }
 }
 
-unsigned
+bool
 bitsetHasMore(uintptr_t* p)
 {
   switch (*p) {
@@ -770,7 +770,8 @@ bitsetHasMore(uintptr_t* p)
 unsigned
 bitsetNext(Context* c, uintptr_t* p)
 {
-  assert(c, bitsetHasMore(p));
+  bool more UNUSED = bitsetHasMore(p);
+  assert(c, more);
 
   switch (*p) {
   case 0: abort(c);
diff --git a/src/machine.cpp b/src/machine.cpp
index 6571e82b40..d2046e815c 100644
--- a/src/machine.cpp
+++ b/src/machine.cpp
@@ -1708,9 +1708,11 @@ isAssignableFrom(Thread* t, object a, object b)
   if (classFlags(t, a) & ACC_INTERFACE) {
     for (; b; b = classSuper(t, b)) {
       object itable = classInterfaceTable(t, b);
-      for (unsigned i = 0; i < arrayLength(t, itable); i += 2) {
-        if (arrayBody(t, itable, i) == a) {
-          return true;
+      if (itable) {
+        for (unsigned i = 0; i < arrayLength(t, itable); i += 2) {
+          if (arrayBody(t, itable, i) == a) {
+            return true;
+          }
         }
       }
     }