[SOLR-8876] Morphlines fails with "No command builder registered for ..." when using Java 9 due to morphline "importCommands" config option attempting to resolve classname globs

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Workaround
• Fix Version/s: 6.5, 7.0
• Component/s: contrib - MapReduce, contrib - morphlines-cell, contrib - morphlines-core
• Labels: Java9
• Assignee: Chris M. Hostetter
• Reporter: Uwe Schindler
• Created: 19/Mar/16 12:31
• Updated: 21/Dec/19 13:06
• Resolved: 08/Mar/17 19:16

Description

When running Solr in java9, and using the morphlines contrib(s) users may encounter vague errors such as...

No command builder registered for COMMAND_NAME

This error comes directly from the morphlines code, and relates to the use of wildcards in the importCommands declaration of of morphlines *.conf files used – for example...

importCommands : ["org.kitesdk.**", "org.apache.solr.**"]

Using wildcards like * and ** in morphline's importCommands config options do not work in java9 due to changes in the underlying JVM classloader.

This issue is tracked up stream in: https://github.com/kite-sdk/kite/issues/469

---

WORK AROUND

The workaround is to only use fully qualified command class names in importCommands declaration, one for each distinct command used in that conf file.

Example:

# Old config, does not work in java9
# importCommands : ["org.kitesdk.**", "org.apache.solr.**"]

# replaced with...

# using globs (foo.bar.* or foo.bar.**) will not work in Java9 due to classpath scanning limitations
# so we enumarate every command (builder) we know this config uses below. (see SOLR-8876)
importCommands : ["org.kitesdk.morphline.stdlib.LogDebugBuilder",
                  "org.apache.solr.morphlines.solr.SanitizeUnknownSolrFieldsBuilder",
                  "org.apache.solr.morphlines.solr.LoadSolrBuilder"]

Issue Links

• is related to: SOLR-8874 Add fixes and workaround for Java 9 Jigsaw (Module System) to Solr tests