Up to date syntax documentation?
pm at netcetera.ch
Thu Oct 15 11:52:38 UTC 2015
On 14.10.15 18:48, Alan Bateman wrote:
> On 14/10/2015 17:14, Philippe Marschall wrote:
>> I'm looking for an up to date syntax documentation for the
>> module-info.java. Specifically I'm looking for the syntax for optional
>> dependencies and specifying the main class. The most up to date
>> information I could find was  but this doesn't cover optional
>> dependencies. Googling suggests the following syntax
>> require optional module-name;
>> But this doesn't seem to work. Googling also suggests there is/was
>> syntax for specifying the main class but none of the example seem to
>> work anymore.
> The main project page  has links to all the current documents,
> including the draft "Modules in the Java Language and JVM" page.
> I suspect it may be a surprise but there isn't any support for optional
> dependences in the proposed design or prototype. At least for the JDK
> modularization effort then we've been able to mostly eliminate the
> original needs for this by moving to services.
Most of my needs for optional dependencies come from annotations. Three
examples come to mind:
1. Lifecycle annotations like (javax.annotation): If code runs within
some container often methods with such annotations are detected and
automatically invoked at the right time. But if the same code runs
outside a container the annotations are not needed and the methods can
simply be invoked explicitly.
2. Additional type check annotations (eg. JSR-305): These annotations
are not needed at runtime but still need to be in the class files for
tools to perform static analysis. Generally all annotations with a
retention policy of class are candidates for optional dependencies.
3. Mapping annotations: Sometimes classes have annotations for specific
mapping technologies. But if they are used without these mapping
technologies then the annotations are not needed at runtime.
> The module main class is not in the module declaration. If you are
> building a modular JAR then you can specify it to the jar command with
> --main-class $MAINCLASS. If the initial module is exploded on the file
> system then you can specify the main class to the java launcher with -m
Where in the JAR does this information end up?
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