To render or retrieve the emitted data, a subscription API must be created. Perform the following steps on how to implement Subscriber<T>:

1. Create a test class TestEmployeeNativeStreamservice that will verify some of the methods in the previous EmployeeNativeStreamservice. Add the following test method that executes processFormUser() using Subscriber<T> implemented through java.util.function.Consumer<T>:

@RunWith(SpringJUnit4ClassRunner.class) 
@WebAppConfiguration 
@ContextConfiguration(classes = {  
SpringDbConfig.class, SpringDispatcherConfig.class }) 
public class TestEmployeeNativeStreamservice { 
 
@Test 
public void testMonoUserA(){ 
 
Consumer<String> convertUser = (str) ->  
         System.out.println("String object: " + str); 
employeeNativeStreamserviceImpl 
.processFormUser("sjct").subscribe(convertUser); 
} 
} 

2. Add another test method that generates a subscriber using a method reference in functional programming. This time, this test case aims to run the getAllAge() method:

@Test 
public void testFluxAgeArray(){ 
      List<Integer> bufferedAge = new ArrayList<>(); 
      employeeNativeStreamserviceImpl 
.getAllAge(new Integer[]{1,2,3,4}) 
.subscribe(bufferedAge::add); 
      for(Integer age: bufferedAge){ 
         System.out.println(age); 
      } 
}

3. Another subscriber that can execute processFormUser() is instantiated using the Reactor Stream's Subscriber<T> API which is depicted in the method as follows:

@Test 
public void testMonoUserC(){ 
  Subscriber<String> subscriber = new Subscriber<String>(){ 
 
      @Override 
      public void onComplete() { 
         System.out.println("Mono Streams ended 
 successfully."); 
      } 
 
      @Override 
      public void onError(Throwable e) { 
         System.out.println("Something wrong happened.  
            Exits now.");      
} 
 
      @Override 
      public void onNext(String name) { 
         System.out.println("String object: " + name); 
      } 
 
      @Override 
      public void onSubscribe(Subscription subs) { 
         subs.request(Long.MAX_VALUE); 
      } 
}; 
 
employeeNativeStreamserviceImpl 
       .processFormUser("sjctrags").subscribe(subscriber);   
} 

4. Save the file. Execute all test cases to view all the results.