Should there be an error for missing classified Jars?

I recently used a maven_install call that looked like this:
```
def load_deps():
maven_install(
name = "parser_maven",
artifacts = [
"org.apache.commons:commons-lang3:3.4",
"junit:junit:4.13",
"org.slf4j:slf4j-simple:1.7.30",
"com.company:client:3.0.0-SNAPSHOT",
],
repositories = [
"https://artifacts/archiva/repository/snapshots/",
],
)
```
Looks good, but my compile didn't seem to work, complaining about missing classes from a transitive dependency of the com.company:client artifact. So I tried adding that artifact directly, adding this to the `artifacts` property:
```
maven.artifact(
group = "com.company.utils",
artifact = "util",
version = "2.1.2-SNAPSHOT",
classifier = "java",
),
```
This is the correct coordinate for this artifact, but I was still having the same issues. So after some troubleshooting, I found three things:
1. For the com.company.utils:util artifact the pom had been uploaded, but the classified version of the jar had not been (this was the root cause of the problem).
1. In the BUILD file for the parser_maven repo the definition for this artifact was:
```
java_library(
name = "com_company_utils_util_java",
exports = [
],
tags = ["maven_coordinates=com.company.utils:util:jar:java2:2.1.2-SNAPSHOT"],
)
```
(notice the missing "jars" property)
1. In the `external/parser_maven/v1/.../2.1.2-SNAPSHOT` directory for the artifact, I had this set of files:
1. .util-java.pom (along with the .md5 and .sha1 versions)
1. .util-java.jar.err (along with the .md5 and .sha1 versions)

So what it looked like is the pom was able to be retrieved but the classified jar was not, since it didn't exist at the time. Given that this was the case should an error have been thrown during the retrieval stage, instead of at the compile stage when the classes were missing? I wouldn't have expected the "@parser_maven//:com_company_utils_util" label to resolve properly if the requested artifact wasn't found.

Start at the maven_install entry point and inspect the generated BUILD definition for com_company_utils_util in external/parser_maven/v1/.../2.1.2-SNAPSHOT, along with the .util-java.jar.err and POM files. Trace how a missing classified JAR is handled during retrieval and define completion as reporting the missing artifact before compilation instead of exposing a misleading resolvable label.

Written by the indexing model from the issue text.