Grails removeFrom() issue - grails

Question

Inside my Applicant domain class I have the following:
static hasMany = [recommendationFiles:ApplicantFile]
static mapping = {recommendationFiles joinTable: [name:"LETTER_FILES", key: "APPLICANT_ID", column: "LETTER_ID"]}
When I do the following:
def applicant = Applicant.findByENumber(session.user.eNumber)
def applicantFiles = applicant.recommendationFiles
println applicantFiles
applicantFiles.each {
applicant.removeFromRecommendationFiles(it)
}
applicant.save(flush:true)
I get this as an error which makes no sense to me:
| Error 2015-04-08 10:41:59,570 [http-bio-8080-exec-10] ERROR errors.GrailsExceptionResolver - ConcurrentModificationException occurred when processi
ng request: [POST] /scholarshipsystem/specialized/index - parameters:
_action_reUpload: Re-Upload
Stacktrace follows:
Message: null
Line | Method
->> 793 | nextEntry in java.util.HashMap$HashIterator
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
| 828 | next in java.util.HashMap$KeyIterator
| 106 | reUpload in scholarshipSystem.SpecializedController$$EP9HMKbd
| 195 | doFilter in grails.plugin.cache.web.filter.PageFragmentCachingFilter
| 63 | doFilter in grails.plugin.cache.web.filter.AbstractFilter
| 895 | runTask in java.util.concurrent.ThreadPoolExecutor$Worker
| 918 | run . . . in ''
^ 662 | run in java.lang.Thread

Answer 1

There's a few ways to make this work. One way is to convert the list to an array and iterate over it.
def list = applicantFiles.toArray()
list.each {
applicant.removeFromRecommendationFiles(it)
}
Another way, if you're just removing the entire collection would be to...
applicant.recommendationFiles*.delete()
applicant.recommendationFiles.clear()