Question

I am getting a NullPointerException while testing Spring Junit test configurations. The issue is with using the @ContextConfiguration and the @Autowired annotation.

When I instantiate the context and get a reference to the bean directly, as shown with the commented out code in the test method, the test runs correctly and succeeds. But when I try to use the @ContextConfiguration and @autowired annotations, with the same XML file attribute I get a NullPointerException in my assertEquals statement. Do you have any idea what I’m doing wrong?

package com.greathouse.helloworld.HelloWorldTest;

import javax.inject.Inject;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import junit.framework.TestCase;

@ContextConfiguration(locations = {"classpath:/resources/application-config.xml"})
@RunWith(SpringJUnit4ClassRunner.class)
public class AppTest extends TestCase
{
    @Autowired
    MessageService messageService;

    @Test
    public void testApp()
    {
        //ApplicationContext context = new ClassPathXmlApplicationContext("classpath:/resources/application-config.xml");
        //messageService = context.getBean("printMessage", MessageService.class);
        assertEquals( messageService.getMessage(), "Hello World" );
    }
}

Answer 1

It looks like messageService did not get autowired. It would help if you put messageService as required.

@Autowired( required = true )

This way when spring context starts spring will tell you why it didn’t autowire your component.
Also as a side note, since you are using JUnit 4 your test does not need to extend from TestCase.