[icedtea-web] RFC: Patch to check the manifest file for main class

[Omair Majid]

On 02/27/2012 05:42 PM, Deepak Bhole wrote:
> Hi,
> 
> This commit introduced a check for main in HEAD:
> http://icedtea.classpath.org/hg/icedtea-web/rev/bd59947fa857
> 
> However it causes an error if the main method is listed in the manifest
> rather than JNLP (e.g.: http://pardemo02.ilog.fr/mapviewer/mapviewer.jnlp)
> 

Thanks for catching this.

> 
> diff -r 4d7bddf0d4de netx/net/sourceforge/jnlp/runtime/JNLPClassLoader.java
> --- a/netx/net/sourceforge/jnlp/runtime/JNLPClassLoader.java	Mon Feb 27 21:58:41 2012 +0100
> +++ b/netx/net/sourceforge/jnlp/runtime/JNLPClassLoader.java	Mon Feb 27 17:40:45 2012 -0500
> @@ -593,6 +593,22 @@
>              mainClass = ad.getMainClass();
>          } else
>              return;
> +
> +        // The main class may be specified in the manifest
> +        if (mainClass == null) {
> +            JARDesc mainJarDesc = file.getResources().getMainJAR();
> +            File f = CacheUtil.getCacheFile(mainJarDesc.getLocation(), null);

A couple of lines below,

tracker.getCacheFile(jars.get(i).getLocation());

is used instead of CacheUtil.getCacheFile. The javadoc of
CacheUtil.getCacheFile notes that "This method returns the file location
only and does not download the resource". Is there any reason to use
CacheUtil over ResourceTracker?

> +            if( f != null) {
> +                try {
> +                    JarFile mainJar = new JarFile(f);
> +                    mainClass = mainJar.getManifest().
> +                            getMainAttributes().getValue("Main-Class");
> +                } catch (IOException ioe) {
> +                    return;
> +                }
> +            }
> +        }
> +

Just throwing this one out there: if there is no jar marked main, should
we try and iterate over all jars to find a jar with a Main-Class in the
manifest file?

Cheers,
Omair