elasticsearch - Java.lang.NullPointerException: Cannot get property ‘x’ on null object - when running a groovy script -

i run groovy script through transport client: script looks this:

if (ctx._source.field.names == null)     ctx._source.field.names=newitems  else     ctx._source.field.names<< newitems;  ctx._source.field.names = ctx._source.field.names.flatten().unique() 

my problem of times works following error:

 caused by: java.lang.illegalargumentexception: failed execute script     @ org.elasticsearch.action.update.updatehelper.executescript(updatehelper.java:256) ~[org.elasticsearch.elasticsearch-2.0.1.jar:2.0.1]     @ org.elasticsearch.action.update.updatehelper.prepare(updatehelper.java:196) ~[org.elasticsearch.elasticsearch-2.0.1.jar:2.0.1]     @ org.elasticsearch.action.update.updatehelper.prepare(updatehelper.java:79) ~[org.elasticsearch.elasticsearch-2.0.1.jar:2.0.1]     @ org.elasticsearch.action.update.transportupdateaction.shardoperation(transportupdateaction.java:170) ~[org.elasticsearch.elasticsearch-2.0    @ org.elasticsearch.action.update.transportupdateaction$3$1.dorun(transportupdateaction.java:227) ~[org.elasticsearch.elasticsearch-2.0.1.    @ org.elasticsearch.common.util.concurrent.abstractrunnable.run(abstractrunnable.java:37) ~[org.elasticsearch.elasticsearch-2.0.1.jar:2.0.1]    @ java.util.concurrent.threadpoolexecutor.runworker(threadpoolexecutor.java:1142) ~[na:1.8.0_74-cedar14]     @ java.util.concurrent.threadpoolexecutor$worker.run(threadpoolexecutor.java:617) ~[na:1.8.0_74-cedar14]     @ java.lang.thread.run(thread.java:745) ~[na:1.8.0_74-cedar14]   caused by: org.elasticsearch.script.groovy.groovyscriptexecutionexception: failed run inline script [if (ctx._source.field.names == null)       ctx._source.field.names=newitems    else       ctx._source.field.names<< newitems;       ctx._source.field.names = ctx._source.field.names.flatten().unique()] using lang [groovy]      @ org.elasticsearch.script.groovy.groovyscriptengineservice$groovyscript.run(groovyscriptengineservice.java:253) ~[org.elasticsearch.     @ org.elasticsearch.action.update.updatehelper.executescript(updatehelper.java:251) ~[org.elasticsearch.elasticsearch-2.0.1.jar:2.0.1]      ... 8 common frames omitted    caused by: java.lang.nullpointerexception: cannot property 'names' on null object      @ org.codehaus.groovy.runtime.nullobject.getproperty(nullobject.java:60) ~[org.codehaus.groovy.groovy-all-2.4.0.jar:2.4.0]      @ org.codehaus.groovy.runtime.invokerhelper.getproperty(invokerhelper.java:172) ~[org.codehaus.groovy.groovy-all-2.4.0.jar:2.4.0]      @ org.codehaus.groovy.runtime.callsite.nullcallsite.getproperty(nullcallsite.java:47) ~[org.codehaus.groovy.groovy-all-2.4.0.jar:2.4.0]      @ org.codehaus.groovy.runtime.callsite.abstractcallsite.callgetproperty(abstractcallsite.java:296) ~[org.codehaus.groovy.groovy-all-2.4.0.     @ 889babff0826c95e16279a9fb1fd2eb97a63e642.run(889babff0826c95e16279a9fb1fd2eb97a63e642:1) ~[na:na]      @ org.elasticsearch.script.groovy.groovyscriptengineservice$groovyscript.run(groovyscriptengineservice.java:248) ~[org.elasticsearch. 

here document example:

{     "field": {       "names": ["a","b","c"],       "a": { "name": "a awesome" },       "b": { "name": "b awesome" },       "c": { "name": "c awesome" }    },    "email": "x@gmail.com" } 

mappings:

"my_index": { "mappings": {   "my_type": {      "properties": {        "email": {          "type": "string",          "analyzer": "email"        },        "field": {          "properties": {            "a": {              "properties": {                "name": {                  "type": "string",                  "analyzer": "lowercase"                 }               }             },             "b": {              "properties": {                "name": {                  "type": "string",                  "analyzer": "lowercase"                 }               }             },             "c": {              "properties": {                "name": {                  "type": "string",                  "analyzer": "lowercase"                 }               }             },             "names": {               "type": "string",               "analyzer": "lowercase"              }            }          }        }     }   } } 

my code:

  override def addterms(id: string, path: string, terms: set[string]): future[unit] = {     val groovyscript =       s"""if (ctx._source.$path == null)           |   ctx._source.$path=newitems           |else           |   ctx._source.$path<< newitems;           |ctx._source.$path = ctx._source.$path.flatten().unique();""".stripmargin     client.execute(elasticdsl.update id id in indexname / documenttype retryonconflict 5 script {       script(groovyscript).params(map("newitems" -> terms.toarray))     }).map(_ => unit)   }       override def update(id: string, field: nestedfieldvalue) = {     client.execute {       elasticdsl.update(id) in indexname / documenttype retryonconflict 5 doc field     }   } 

i looked on document script fails on, , tried manually run script using curl, , worked. document not problem.

i running update 38 documents, meaning run 38 times. exception thrown on different document every time try update beginning (meaning running again on 38 documents)

not sure missing here. ideas? thanks!