java - Any way to have a method that create new instances of a class passed by parameter? -

i creating tests in have create lists send object under test. in order create lists, have method called createentitieslist, in send number of elements in list , receive list filled elements (with valid, random generated values). basic, able create lists of different types, instance

list<professor> list = createentitylist(professor.class); list<student> list = createentitylist(student.class); 

of course professor , students have different attributes fill out.

my current method one:

    private <t> list<t> getentitylist(class<t> entitytype, int numberofitems) {         list<t> entities = new arraylist<t>();          (int = 0; < numberofitems; i++) {             if (entitytype.equals(professorentity.class)) {                 entities.add((t) createprofessorentity(i));             } else {                 throw new unsupportedoperationexception("not yet implemented");             }          }          return entities;     }      @suppresswarnings("unchecked")     private <t> t createprofessorentity(int index) {         professorentity entity = new professorentity();         entity.settitle(string.format("title %s", index));         entity.setnamecompany);         return (t) entity;     } 

ok, works, feel didn't achieved goal, because have create new method , "if" statement each new type of class want create. on other side, not see improvements make required less effort.

is there way can improve code able call 1 method create entities of desired type reduce effort add new supported class?

ps: effort not big, learn because useful in future.

yes, can. start defining interface:

public interface entitycreator<t> {     t create(int index); } 

and pass instance of interface method:

private <t> list<t> getentitylist(entitycreator<t> creator, int numberofitems) {     list<t> entities = new arraylist<t>();      (int = 0; < numberofitems; i++) {         entities.add(creator.create(i));     }      return entities; } 

then, create 10 professor entities:

list<professorentity> list = getentitylist(this::createprofessorentity, 10); 

if you're not under java 8 yet, you'll have use inner classes:

list<professorentity> list = getentitylist(new entitycreator<professorentity>() {     @override     public professorentity create(int index) {         return createprofessorentity(i);     } }, 10);