problem with java task attribute jvmarg when value is ""

[Frederic Chalons]

Hi,

My problem involved the attribute jvmarg set to a property which value
is ""...

Using Ant 1.6.4, I am using the java task to launch various process:

    /        <java classname="${classname}">/
    /            <arg value="${arg1}" />/
    /            <arg value="${arg2}" />/
    /            <jvmarg value="${jvmarg1}" />/
    /            <jvmarg value="${jvmarg2}" />/
    /        </java>/

For each class the properties (arg1, arg2, jvmarg1, jvmarg2,etc. ) are
loaded from xml file.
After that, for each undefined property, its value is set to "".
As a property cannot be overwritten, it behaves as defining a default value.

This is working fine as long as jvmarg1 & jvmarg2 properties have a
value but breaks when they use "" as default value.
Running ant -debug gives the following:

    /''/
    /''/

    /The ' characters around the executable and arguments are/
    /not part of the command./
    /     [java] Exception in thread "main" java.lang.NoClassDefFoundError:/

    /BUILD FAILED/

It seems that empty jvmarg is the caused but I need to find a way to
inhibit jvmarg attribute when the associated property is not used.

This basically, the same problem as mentionned at this link:
http://www.jguru.com/forums/view.jsp?EID=1275301
But the switch/case-like solution given is not flexible enough for my needs.

Hope somebody faced & solved this issue before ;)

Thank you,
Frederic CHALONS

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[Steve Loughran]

Frederic Chalons wrote:

> Hi,
>
> My problem involved the attribute jvmarg set to a property which value
> is ""...
>
> Using Ant 1.6.4, I am using the java task to launch various process:
>
>    /        <java classname="${classname}">/
>    /            <arg value="${arg1}" />/
>    /            <arg value="${arg2}" />/
>    /            <jvmarg value="${jvmarg1}" />/
>    /            <jvmarg value="${jvmarg2}" />/
>    /        </java>/
>
> For each class the properties (arg1, arg2, jvmarg1, jvmarg2,etc. ) are
> loaded from xml file.
> After that, for each undefined property, its value is set to "".
> As a property cannot be overwritten, it behaves as defining a default
> value.
>
> This is working fine as long as jvmarg1 & jvmarg2 properties have a
> value but breaks when they use "" as default value.
> Running ant -debug gives the following:
>
>    /''/
>    /''/
>
>    /The ' characters around the executable and arguments are/
>    /not part of the command./
>    /     [java] Exception in thread "main" java.lang.NoClassDefFoundError:/
>
>    /BUILD FAILED/
>
> It seems that empty jvmarg is the caused but I need to find a way to
> inhibit jvmarg attribute when the associated property is not used.

Alternatively, you need a default JVM argument that can be used multiple
times and has no side effects, and make that the default.

the -ea option to enable assertions for a package may work there...


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[Frederic Chalons]

Steve Loughran wrote:

> Frederic Chalons wrote:
>
>> Hi,
>>
>> My problem involved the attribute jvmarg set to a property which
>> value is ""...
>>
>> Using Ant 1.6.4, I am using the java task to launch various process:
>>
>>    /        <java classname="${classname}">/
>>    /            <arg value="${arg1}" />/
>>    /            <arg value="${arg2}" />/
>>    /            <jvmarg value="${jvmarg1}" />/
>>    /            <jvmarg value="${jvmarg2}" />/
>>    /        </java>/
>>
>> For each class the properties (arg1, arg2, jvmarg1, jvmarg2,etc. )
>> are loaded from xml file.
>> After that, for each undefined property, its value is set to "".
>> As a property cannot be overwritten, it behaves as defining a default
>> value.
>>
>> This is working fine as long as jvmarg1 & jvmarg2 properties have a
>> value but breaks when they use "" as default value.
>> Running ant -debug gives the following:
>>
>>    /''/
>>    /''/
>>
>>    /The ' characters around the executable and arguments are/
>>    /not part of the command./
>>    /     [java] Exception in thread "main"
>> java.lang.NoClassDefFoundError:/
>>
>>    /BUILD FAILED/
>>
>> It seems that empty jvmarg is the caused but I need to find a way to
>> inhibit jvmarg attribute when the associated property is not used.
>
>
> Alternatively, you need a default JVM argument that can be used
> multiple times and has no side effects, and make that the default.
>
> the -ea option to enable assertions for a package may work there...
>
>
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> To unsubscribe, e-mail: [hidden email]
> For additional commands, e-mail: [hidden email]

Hi Steve,

Thank you for your insight.

By the way, I was given another workaround by defining a system property
as default value.
ex: <property name="arg1" value="-Dtoto="titi" />

This not very elegant but it works as a charm :-)

Regards,
Frederic

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