Launching single file source code program - "error: class found on application class path"

[Jonathan Gibbons]

On 6/18/18 2:33 PM, Attila Szegedi wrote:
> On 2018. Jun 18., at 19:52, Jonathan Gibbons <jonathan.gibbons at oracle.com> wrote:
>> On 06/17/2018 03:56 AM, Jaikiran Pai wrote:
>>> […]
>>>
>>> The /tmp/foo-bar directory now consists of A.class and A.java. I then went ahead and (tried) to launch the A.java using the new feature as previously:
>>>
>>>> java A.java
>>> I now get this error message:
>>>
>>> error: class found on application class path: A
>>> […]
>>> 2. Why is this an error? Is it intentional?
>> This is the intended behavior, to avoid the ambiguity of having the class on the classpath (which defaults to the current directory) and the internally-compiled class generated from the source file.
> Is this really ambiguous?
>
> If the user runs “java A.java”, their intent is clearly to run the source code file. The file name is explicitly spelt out in the command.
>
> If the user runs "java A”, then – if only from a purely backwards-compatible perspective – it should run the precompiled class; same way “java” command worked before this feature existed. I can see how one might argue user's intent was ambiguous in this case, though. (But then, it isn't the case original poster asked about.)
>
> Attila.
>

Yes, we wanted to avoid any confusion between the possibility of the 
class being on the classpath and being specified as a source file.

-- Jon