diff --git a/Foundation/CPArray.j b/Foundation/CPArray.j
index 866fd8dad..4134df19f 100755
--- a/Foundation/CPArray.j
+++ b/Foundation/CPArray.j
@@ -108,7 +108,9 @@ CPEnumerationReverse    = 1 << 1;
 */
 + (id)alloc
 {
-    return [];
+	var result = [];
+	result.isa = [self class];
+    return result;
 }
 
 /*!
diff --git a/Foundation/CPData.j b/Foundation/CPData.j
index 0a75abd36..8e8c20340 100644
--- a/Foundation/CPData.j
+++ b/Foundation/CPData.j
@@ -36,7 +36,9 @@
 
 + (id)alloc
 {
-    return new CFMutableData();
+    result = new CFMutableData();
+	result.isa = [self class];
+	return result;
 }
 
 + (CPData)data
diff --git a/Foundation/CPDate.j b/Foundation/CPDate.j
index 3ecdd21a4..f04b3849b 100644
--- a/Foundation/CPDate.j
+++ b/Foundation/CPDate.j
@@ -39,7 +39,9 @@ var CPDateReferenceDate = new Date(Date.UTC(2001, 1, 1, 0, 0, 0, 0));
 
 + (id)alloc
 {
-    return new Date;
+	var result = new Date;
+	result.isa = [self class];
+    return result;
 }
 
 + (id)date
diff --git a/Foundation/CPDictionary.j b/Foundation/CPDictionary.j
index 61634cd67..3d42951c2 100755
--- a/Foundation/CPDictionary.j
+++ b/Foundation/CPDictionary.j
@@ -84,7 +84,9 @@
 */
 + (id)alloc
 {
-    return new CFMutableDictionary();
+	var result = new CFMutableDictionary();
+	result.isa = [self class];
+    return result;
 }
 
 /*!
diff --git a/Foundation/CPException.j b/Foundation/CPException.j
index 770c6ad63..7a9c8c959 100755
--- a/Foundation/CPException.j
+++ b/Foundation/CPException.j
@@ -54,6 +54,7 @@ if (input == nil)
 */
 + (id)alloc
 {
+	if ([self class] !== CPException) return [super alloc];
     return new Error();
 }
 
diff --git a/Foundation/CPNumber.j b/Foundation/CPNumber.j
index a0bbef39e..a65949a88 100644
--- a/Foundation/CPNumber.j
+++ b/Foundation/CPNumber.j
@@ -43,7 +43,9 @@ var __placeholder   = new Number(),
 
 + (id)alloc
 {
-    return __placeholder;
+	var result = new Number();
+	result.isa = [self class];
+    return result;
 }
 
 + (id)numberWithBool:(BOOL)aBoolean
diff --git a/Foundation/CPString.j b/Foundation/CPString.j
index 547294939..c6a0d29d3 100644
--- a/Foundation/CPString.j
+++ b/Foundation/CPString.j
@@ -91,6 +91,7 @@ var CPStringRegexSpecialCharacters = [
 */
 + (id)alloc
 {
+	if ([self class] !== CPString) return [super alloc];
     return new String;
 }
 
@@ -134,7 +135,14 @@ var CPStringRegexSpecialCharacters = [
 */
 - (id)initWithString:(CPString)aString
 {
-    return String(aString);
+    if ([self class] === CPString) 
+        return String(aString);
+
+    var result = new String(aString);
+
+    result.isa = [self class];
+
+    return result;
 }
 
 /*!
diff --git a/Foundation/CPURL.j b/Foundation/CPURL.j
index 1486baad3..a79e1aae4 100644
--- a/Foundation/CPURL.j
+++ b/Foundation/CPURL.j
@@ -54,7 +54,9 @@ CPURLCustomIconKey                  = @"CPURLCustomIconKey";
 
 + (id)alloc
 {
-    return new CFURL();
+    var result = new CFURL();
+	result.isa = [self class];
+	return result;
 }
 
 - (id)init
@@ -81,7 +83,9 @@ CPURLCustomIconKey                  = @"CPURLCustomIconKey";
 
 - (id)initWithString:(CPString)URLString relativeToURL:(CPURL)aBaseURL
 {
-    return new CFURL(URLString, aBaseURL);
+    var result = new CFURL(URLString, aBaseURL);
+	result.isa = [self class];
+	return result;
 }
 
 + (id)URLWithString:(CPString)URLString relativeToURL:(CPURL)aBaseURL
diff --git a/Tests/Foundation/SubclassTollFreeTest.j b/Tests/Foundation/SubclassTollFreeTest.j
new file mode 100644
index 000000000..f7b6191b5
--- /dev/null
+++ b/Tests/Foundation/SubclassTollFreeTest.j
@@ -0,0 +1,138 @@
+@implementation SubclassTollFreeTest : OJTestCase
+
+- (void)testThatSubclassTollFreeDoesAllowForSubclassingDictionary
+{
+	var target = [[MyDict alloc] init];
+	[OJAssert assert:@"a" equals:[target newMessage]];
+	[OJAssert assert:0 equals:[target count]];
+}
+
+- (void)testThatSubclassTollFreeDoesAllowForSubclassingString
+{
+	var target = [[MyString alloc] initWithString:@"adsf"];
+	[OJAssert assert:@"a" equals:[target newMessage]];
+	[OJAssert assert:4 equals:[target length]];
+	
+	var target2 = "agdsa";
+	[OJAssert assertThrows:function(){ [target2 newMessage]; }];
+	[OJAssert assert:5 equals:[target2 length]];
+}
+
+- (void)testThatSubclassTollFreeDoesAllowForSubclassingNumber
+{
+	var target = [[MyNum alloc] init];
+	[OJAssert assert:@"a" equals:[target newMessage]];
+	[OJAssert assertFalse:[target isEqualToNumber:5]];
+}
+
+- (void)testThatSubclassTollFreeDoesAllowForSubclassingException
+{
+	var target = [[MyException alloc] init];
+	[OJAssert assert:@"a" equals:[target newMessage]];
+	// there are no internal properties to test here.. so no need to jimmyrig it.
+}
+
+- (void)testThatSubclassTollFreeDoesAllowForSubclassingArray
+{
+	var target = [[MyArray alloc] initWithObjects:@"a"];
+	[OJAssert assert:@"a" equals:[target newMessage]];
+	[OJAssert assert:1 equals:[target count]];
+}
+
+- (void)testThatSubclassTollFreeDoesAllowForSubclassingDate
+{
+	var target = [[MyDate alloc] init];
+	[OJAssert assert:@"a" equals:[target newMessage]];
+	[OJAssert assertTrue:[target timeIntervalSince1970] > 0];
+}
+
+- (void)testThatSubclassTollFreeDoesAllowForSubclassingData
+{
+	var target = [[MyData alloc] initWithRawString:@"b"];
+	[OJAssert assert:@"a" equals:[target newMessage]];
+	[OJAssert assert:@"b" equals:[target rawString]];
+}
+
+- (void)testThatSubclassTollFreeDoesAllowForSubclassingURL
+{
+	var target = [[MyURL alloc] initWithString:@"http://www.google.com"];
+	[OJAssert assert:@"a" equals:[target newMessage]];
+	[OJAssert assert:@"http://www.google.com" equals:[target absoluteString]];
+}
+
+
+@end
+
+@import <Foundation/CPDictionary.j>
+
+@implementation MyDict : CPDictionary
+
+- (id)newMessage
+{
+	return "a";
+}
+
+@end
+
+@implementation MyNum : CPNumber
+
+- (id)newMessage
+{
+	return "a";
+}
+
+@end
+
+@implementation MyString : CPString
+
+- (id)newMessage
+{
+	return "a";
+}
+
+@end
+
+@implementation MyException : CPException
+
+- (id)newMessage
+{
+	return "a";
+}
+
+@end
+
+@implementation MyArray : CPArray
+
+- (id)newMessage
+{
+	return "a";
+}
+
+@end
+
+@implementation MyDate : CPDate
+
+- (id)newMessage
+{
+	return "a";
+}
+
+@end
+
+@implementation MyData : CPData
+
+- (id)newMessage
+{
+	return "a";
+}
+
+@end
+
+@implementation MyURL : CPURL
+
+- (id)newMessage
+{
+	return "a";
+}
+
+@end