java - MongoDB DBCollection.insert() returns null as WriteResult? -

will insert(list) return null?

writeresult result = collection.insert(list<dbobject>); result.geterror()  -->throws nullpointeexception 

in above snippet, may cause return of null writeresult?

can try providing basicdblist, contains basicdbobject instances.

for example:

basicdbobject updateobject = new basicdbobject(); basicdblist dblist = createlist(objects); updateobject.append("$push", new basicdbobject("collection", dblist));  writeresult result = collection.insert(dblist);  ... private basicdblist createlist(list<sampleobject> list) {   basicdblist result = new basicdblist();   (sampleobject obj: list) {     basicdbobject dbobject = new basicdbobject();     dbcar.append("name", obj.getname()); //for exmaple     result.add(dbobj);   }   return result;  }