Error: Failed to load class com.linkedin.dualip.preprocess.MatchingDataGenerator.

Try to follow the instructions in the document. When I try to run the demo code to covert the matching data, the error pops out. Here is the full log:

:: loading settings :: url = jar:file:/usr/local/spark/jars/ivy-2.4.0.jar!/org/apache/ivy/core/settings/ivysettings.xml
Ivy Default Cache set to: /Users/liubo.li/.ivy2/cache
The jars for the packages stored in: /Users/liubo.li/.ivy2/jars
org.apache.spark#spark-avro_2.12 added as a dependency
:: resolving dependencies :: org.apache.spark#spark-submit-parent-14453ece-ca22-46fe-966c-cc48203274b1;1.0
confs: [default]
found org.apache.spark#spark-avro_2.12;3.1.1 in central
found org.spark-project.spark#unused;1.0.0 in central
:: resolution report :: resolve 217ms :: artifacts dl 4ms
:: modules in use:
org.apache.spark#spark-avro_2.12;3.1.1 from central in [default]
org.spark-project.spark#unused;1.0.0 from central in [default]
---------------------------------------------------------------------
| | modules || artifacts |
| conf | number| search|dwnlded|evicted|| number|dwnlded|
---------------------------------------------------------------------
| default | 2 | 0 | 0 | 0 || 2 | 0 |
---------------------------------------------------------------------
:: retrieving :: org.apache.spark#spark-submit-parent-14453ece-ca22-46fe-966c-cc48203274b1
confs: [default]
0 artifacts copied, 2 already retrieved (0kB/4ms)
23/10/17 12:01:41 WARN NativeCodeLoader: Unable to load native-hadoop library for your platform... using builtin-java classes where applicable
Error: Failed to load class com.linkedin.dualip.preprocess.MatchingDataGenerator.
log4j:WARN No appenders could be found for logger (org.apache.spark.util.ShutdownHookManager).
log4j:WARN Please initialize the log4j system properly.
log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info.

Start by retracing the document's demo instructions and the command used to convert the matching data, then investigate why Spark cannot load com.linkedin.dualip.preprocess.MatchingDataGenerator. The work is done when the documented demo runs successfully and converts the matching data without the class-loading error.