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[JAVA] Double.parseDouble(null) throw NullPointerException

Message ID CABc96T_dL8gN9LwtE+Gb_WuzAv1XvCaU+rbZkxhNb-Wb=EdBJw@mail.gmail.com
State New
Headers show

Commit Message

Jie Liu Aug. 9, 2011, 4:41 p.m. UTC 
Hi Tom,

RTEMS does not have virtual memory management, so there is no error
when access the 0 address on rtems.
So 'str->length()' donot throw NPE and just return an meaningless value.

Ps: There is a test:
http://code.google.com/p/rtemsgcj/source/browse/trunk/algorithm/20110810NPE/?r=127,
npe.c is the main file and *.scn is the output.

Thanks,
Jie

2011/8/8 Tom Tromey <tromey@redhat.com>:
>>>>>> "Jie" == Jie Liu <lj8175@gmail.com> writes:
>
> Jie> +  if(str == NULL)
> Jie> +      throw new NullPointerException();
> Jie> +
> Jie>    int length = str->length();
>
> Why doesn't 'str->length()' throw the NPE?
>
> Tom
>

The testsuite/Throw_2.java has been PASS after this patch. what do you
think about this patch?

Thanks,
Jie

Comments

Tom Tromey Aug. 9, 2011, 5:32 p.m. UTC | #1 
>>>>> "Jie" == Jie Liu <lj8175@gmail.com> writes:

Jie> RTEMS does not have virtual memory management, so there is no error
Jie> when access the 0 address on rtems.
Jie> So 'str->length()' donot throw NPE and just return an meaningless value.

If you compile the Java parts of the library with -fcheck-references, it
should work.  This is something you have to set up as part of the port,
as it is decided at (libgcj-) configure time.

This won't help with the native code.  IIRC in the end we just gave up
on that; if you wanted real correctness you would have to add a null
check at every dereference in the C++ code.  I believe Andrew had a g++
patch to do this in the compiler, but it was rejected.

Tom
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Patch

=========== The first mail, for adding Joel ===========
Hi,

When I use gcj on an RTOS(RTEMS), Double.parseDouble(null) throw
NumberFormatException, but it should throw NullPointerException. So I
add the patch below:

Index: natVMDouble.cc
===================================================================
--- natVMDouble.cc	(revision 172224)
+++ natVMDouble.cc	(working copy)
@@ -19,6 +19,7 @@ 
 #include <java/lang/VMDouble.h>
 #include <java/lang/Character.h>
 #include <java/lang/NumberFormatException.h>
+#include <java/lang/NullPointerException.h>
 #include <jvm.h>

 #include <stdio.h>
@@ -162,6 +163,9 @@ 
 jdouble
 java::lang::VMDouble::parseDouble(jstring str)
 {
+  if(str == NULL)
+      throw new NullPointerException();
+
   int length = str->length();

   while (length > 0