google app engine - Unable to Persist using latest Cloud Endpoint Backend defaults in AppEngine 1.8.2 -

i have created multiple endpoints in past using appengine 1.7, jre 1.6, , different google account. data classes follow tutorial examples closely.

with new project, unable persist simple bean, receiving following error when running api explorer. error occurs both running locally , running on appengine.

500 internal server error { "error": { "message": "javax.jdo.jdofatalinternalexception: key value passed construct singlefieldidentity of type \"class javax.jdo.identity.stringidentity\" class \"class com.jdub.minorplanets.mapsector\" null.\nnestedthrowables:\norg.datanucleus.exceptions.nucleusexception: key value passed construct singlefieldidentity of type \"class javax.jdo.identity.stringidentity\" class \"class com.jdub.minorplanets.mapsector\" null.", "code": 503,
"errors": [ { "domain": "global", "reason": "backenderror", "message": "javax.jdo.jdofatalinternalexception: key value passed construct singlefieldidentity of type \"class javax.jdo.identity.stringidentity\" class \"class com.jdub.minorplanets.mapsector\" null.\nnestedthrowables:\norg.datanucleus.exceptions.nucleusexception: key value passed construct singlefieldidentity of type \"class javax.jdo.identity.stringidentity\" class \"class com.jdub.minorplanets.mapsector\" null." } ] } }

my data class simple , stripped down version exhibits error:

@persistencecapable(identitytype = identitytype.application) public class mapsector { @primarykey @persistent(valuestrategy = idgeneratorstrategy.identity) @extension(vendorname="datanucleus", key="gae.encoded-pk", value="true") private string encodedkey;  @persistent private string sectorid;    public mapsector(string sectorid) {     super();     this.sectorid = sectorid; }  public mapsector() {     super(); }   public string getencodedkey() {     return encodedkey; }  /**  * @return sectorid  */ public string getsectorid() {     return sectorid; }  /**  * @param sectorid sectorid set  */ public void setsectorid(string sectorid) {     this.sectorid = sectorid; } } 

the endpoint generated using eclipse plug-in.

at point, believe data nucleus enhancers not getting launched in project. difference see use of app engine 1.8.2 in new project , java 1.7. although using different google account, don't believe issue receive errors on localhost well.

here libs in use project:

• appengine-api-1.0-sdk-1.8.2.jar
• appengine-api-labs.jar
• appengine-endpoints.jar
• appengine-jsr107cache-1.8.2.jar
• asm-4.0.jar
• datanucleus-api-jdo-3.1.3.jar
• datanucleus-api-jpa-3.1.3.jar
• datanucleus-appengine-2.1.2.jar
• datanucleus.core-3.1.3.jar
• gcm-server.jar
• geronimo-jpa_2.0_spec-1.0.jar
• jdo-api-3.0.1.jar
• json_simple-1.1.jar
• jsr107.cache-1.1.jar
• jta-1.1.jar

this driving me nuts. have compared repeatedly working projects , sample code , not see problem. not see similar errors reported.

what need change in configuration have identity set endpoint/datanucleus/appengine code?

other things have tried:

1. i have tried revert java 1.6 no benefit.
2. i have deleted backend project , re-created.

i hope looking for. i've been there , drove me nuts. worked me.

https://stackoverflow.com/a/15014679/2695621

cheers