due to a crash files end up being 0 sized resulting in this stack trace:

STACK 0
18:14 java.util.zip.ZipException: zip file is empty
18:14 at java.util.zip.ZipFile.open(Native Method)
18:14 at java.util.zip.ZipFile.<init>(ZipFile.java:215)
18:14 at java.util.zip.ZipFile.<init>(ZipFile.java:145)
18:14 at java.util.jar.JarFile.<init>(JarFile.java:153)
18:14 at java.util.jar.JarFile.<init>(JarFile.java:117)
18:14 at org.jboss.tools.project.examples.internal.discovery.xpl.DiscoveryRegistryStrategy.processBundle(DiscoveryRegistryStrategy.java:137)
18:14 at org.jboss.tools.project.examples.internal.discovery.xpl.DiscoveryRegistryStrategy.processBundles(DiscoveryRegistryStrategy.java:126)
18:14 at org.jboss.tools.project.examples.internal.discovery.xpl.DiscoveryRegistryStrategy.onStart(DiscoveryRegistryStrategy.java:78)
18:14 at org.eclipse.core.internal.registry.ExtensionRegistry.<init>(ExtensionRegistry.java:725)
18:14 at org.jboss.tools.project.examples.internal.discovery.xpl.ExternalBundleDiscoveryStrategy.performDiscovery(ExternalBundleDiscoveryStrategy.java:125)

files shoulnd't be put into cache before completely downloaded.