dynamic invokers example StringConcat

[Artem Ervits <ar...@gmail.com>]

hello all,

I'm looking at the example

https://pig.apache.org/docs/r0.15.0/api/org/apache/pig/builtin/GenericInvoker.html

-- invoking a method on an object
 DEFINE StringConcat InvokeForString('java.lang.String.concat',
'String String', 'false')
 concatenations = FOREACH strings GENERATE StringConcat(str1, str2);

it's failing with


Caused by: java.lang.RuntimeException: could not instantiate
'InvokeForString' with arguments '[java.lang.String.concat, String
String, false]'
	at org.apache.pig.impl.PigContext.instantiateFuncFromSpec(PigContext.java:772)
	at org.apache.pig.newplan.logical.expression.UserFuncExpression.getFieldSchema(UserFuncExpression.java:222)
	at org.apache.pig.newplan.logical.optimizer.FieldSchemaResetter.execute(SchemaResetter.java:264)
	at org.apache.pig.newplan.logical.expression.AllSameExpressionVisitor.visit(AllSameExpressionVisitor.java:143)
	at org.apache.pig.newplan.logical.expression.UserFuncExpression.accept(UserFuncExpression.java:113)
	at org.apache.pig.newplan.ReverseDependencyOrderWalker.walk(ReverseDependencyOrderWalker.java:70)


I saw a similar post but I'm not clear what PIG_CLASSPATH has anything
to do with fixing this. Do I need to set JAVA on PIG_CLASSPATH?