ERROR org.apache.pig.tools.grunt.Grunt - ERROR 1070: Could not resolve

I was trying out Pig UDF samples from Hadoop definitive guide. Every time i tried executing com.hadoopbook.pig.IsGoodQuality UDF like this i got ERROR org.apache.pig.tools.grunt.Grunt - ERROR 1070: Could not resolve com.hadoop.pig.IsGoodQuality using imports: error

grunt< filtered_records = filter records by temp != 9999 and com.hadoop.pig.IsGoodQuality(quality);2014-05-17 15:39:10,445 [main] ERROR org.apache.pig.tools.grunt.Grunt - ERROR 1070: Could not resolve com.hadoop.pig.IsGoodQuality using imports: [, java.lang., org.apache.pig.builtin., org.apache.pig.impl.builtin.]Details at logfile: /usr/lib/hue/pig_1400366300986.log

The way to fix that problem is by using -Dpig.additional.jars=pig-examples.jar while starting pig

pig -Dpig.additional.jars=pig-examples.jar