rest - Java – multiple call on DAO causes exception (wildly, jboss) -

i building java rest application. therefor using jboss on wildfly 8 server.

the following code causes exception: jbas011469: transaction required perform operation (either use transaction or extended persistence context)

@path("/users") @stateless public class usersendpoint {      @post     @produces(mediatype.application_json)     @consumes(mediatype.application_json)     public response create(user user) {          try {             this.checkusername(user.getusername());             this.checkemail(user.getemail());             return response.ok(userdao.create(user)).build();;         } catch (ioexception e) {             return response.status(response.status.not_acceptable)                            .entity(e.getmessage())                            .build();          } catch (exception e) {             return response.status(response.status.not_acceptable)                            .entity(e.getmessage())                            .build();         }     }      @post     @path("username")     @produces(mediatype.application_json)     @consumes(mediatype.text_html)     public response username(string username) {          try {             this.checkusername(username);             return response.ok().build();         } catch (exception e) {             return response.status(response.status.not_acceptable)                            .entity(entity)                            .build();         }     }      @post     @path("email")     @produces(mediatype.application_json)     @consumes(mediatype.text_html)     public response email(string email) {         try {             this.checkemail(email);             return response.ok().build();         } catch (exception e) {             return response.status(response.status.not_acceptable)                            .entity(this.validator.validateerror(null, e))                            .build();         }     }      private void checkusername(string username) throws ioexception {         try {             userdao.get(username);             throw new ioexception("username taken allready.");         }         catch (ioexception e) { throw e; }         catch (exception e) { system.out.println("username can used"); }     }      private void checkemail(string email) throws ioexception {         try {             userdao.getbyemail(email);             throw new ioexception("email taken allready.");         }         catch (ioexception e) { throw e; }         catch (exception e) { system.out.println("email can used"); }     } } 

the public response email(string email) , public response username(string username) functions working fine. problem seems call of both functions through public response create(user user) function:

... try {     this.checkusername(user.getusername());     this.checkemail(user.getemail());     ... 

so when have correct username duplicate email exception jbas011469: transaction required perform operation (either use transaction or extended persistence context) going thrown in userdao.getbyemail(email). when have duplicate username instead ioexception("username taken allready.") going thrown expected.

when change order of functions to:

... try {     this.checkemail(user.getemail());     this.checkusername(user.getusername());     ... 

the same problem occurs in userdao.get(username) , correct email , duplicate username.

edit

when removing throw new ioexception("username taken allready."); in private void checkusername(string username) throws ioexception { } second dao call working fine. problem seems exception thrown. how can solve that?

my userdao

public interface userdao {     public user create(user user) throws exception;     public user get(string username) throws exception;     public user getbyemail(string email) throws exception; } 

my userbean

@stateless @remote(userdao.class) public class userbean implements userdao {      // injected database connection:     @persistencecontext private entitymanager em;      @override     public user create(user user) throws exception {         em.persist(user);         return user;     }      @override     public user get(string username) throws exception {         return em.createnamedquery(user.query_username, user.class)                  .setparameter("username", username)                  .getsingleresult();     }      @override     public user getbyemail(string email) throws exception {         return em.createnamedquery(user.query_email, user.class)                  .setparameter("email", email)                  .getsingleresult();     } }