AppConfig encounter NullPointerException Error

Question

Update: I downloaded authors source code, same issue happeded..... pom.xml file> https://gist.github.com/jianheMark/09c8e250f43d436ba51d27971c4ea5a2 Follow tutorial. But when I run it, then there is NullPointerException Error. I using Intellj.

Exception in thread "main" java.lang.NullPointerException: Cannot invoke "Object.getClass()" because "cause" is null

All three classes in same package. I already checked on internet. I even comment out other xml files.

package javaconfig;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class AppConfig{

    @Bean(initMethod = "customInit")
    public Customer customer(){
        return new Customer();
    }
}


public class Customer {
    public Customer() {
        System.out.println("Default Constructor.......");
    }
    public void customInit() {
        System.out.println("Customer Init......");
    }
}



package javaconfig;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
public class JavaConfigMain {
    public  static void main(String[] args){
       
        new AnnotationConfigApplicationContext(AppConfig.class);
    }
}

I follow this tutorial: https://www.youtube.com/watch?v=0awHx-346Is&list=PLGTrAf5-F1YIUo_AWConTTY_VWGJnveT8&index=15

Full Error Code:

Exception in thread "main" java.lang.NullPointerException: Cannot invoke "Object.getClass()" because "cause" is null
    at org.springframework.cglib.core.CodeGenerationException.<init>(CodeGenerationException.java:25)
    at org.springframework.cglib.core.ReflectUtils.defineClass(ReflectUtils.java:587)
    at org.springframework.cglib.core.AbstractClassGenerator.generate(AbstractClassGenerator.java:363)
    at org.springframework.cglib.proxy.Enhancer.generate(Enhancer.java:585)
    at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:110)
    at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData$3.apply(AbstractClassGenerator.java:108)
    at org.springframework.cglib.core.internal.LoadingCache$2.call(LoadingCache.java:54)
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
    at org.springframework.cglib.core.internal.LoadingCache.createEntry(LoadingCache.java:61)
    at org.springframework.cglib.core.internal.LoadingCache.get(LoadingCache.java:34)
    at org.springframework.cglib.core.AbstractClassGenerator$ClassLoaderData.get(AbstractClassGenerator.java:134)
    at org.springframework.cglib.core.AbstractClassGenerator.create(AbstractClassGenerator.java:319)
    at org.springframework.cglib.proxy.Enhancer.createHelper(Enhancer.java:572)
    at org.springframework.cglib.proxy.Enhancer.createClass(Enhancer.java:419)
    at org.springframework.context.annotation.ConfigurationClassEnhancer.createClass(ConfigurationClassEnhancer.java:137)
    at org.springframework.context.annotation.ConfigurationClassEnhancer.enhance(ConfigurationClassEnhancer.java:109)
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.enhanceConfigurationClasses(ConfigurationClassPostProcessor.java:447)
    at org.springframework.context.annotation.ConfigurationClassPostProcessor.postProcessBeanFactory(ConfigurationClassPostProcessor.java:268)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:325)
    at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:147)
    at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:746)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:564)
    at org.springframework.context.annotation.AnnotationConfigApplicationContext.<init>(AnnotationConfigApplicationContext.java:93)
    at javaconfig.JavaConfigMain.main(JavaConfigMain.java:12)

pom.xml file is not the issue . All works fine. But I don't know why. — jian, Jul 21 '21 at 06:01
what's your actual issue? And what are you exactly trying to achieve and run? — devReddit, Jul 21 '21 at 06:09
@devReddit in the console> I should able to print out Default Constructor....... — jian, Jul 21 '21 at 06:12
I even tried: `@Bean public Customer customer(){ Customer customer1 = new Customer(); return customer1; }` — jian, Jul 21 '21 at 06:29
Which JDK, and please post a minimal pom.xml so we can see which versions of spring you are using. — tgdavies, Jul 21 '21 at 06:32
@tgdavies https://gist.github.com/jianheMark/09c8e250f43d436ba51d27971c4ea5a2 JDK 16 — jian, Jul 21 '21 at 06:37
@devReddit https://gist.github.com/jianheMark/09c8e250f43d436ba51d27971c4ea5a2 — jian, Jul 21 '21 at 06:39
JDK: https://www.dropbox.com/s/giq5wpwkquhttz0/Capture.PNG?dl=0 — jian, Jul 21 '21 at 06:42
Does this answer your question? [Avoiding NullPointerException in Java](https://stackoverflow.com/questions/271526/avoiding-nullpointerexception-in-java) — Martin Zeitler, Jul 21 '21 at 06:55
@devReddit I copied the author's code from github. Still failed. So i guess that's it. — jian, Jul 21 '21 at 07:09
@JianHe, I successfully run that code in my ide, so, I guess there's something with the version compatibility, and project configuration. — devReddit, Jul 21 '21 at 09:51
I don't think that version is compatible with JDK 16. It works when I use 1.8 — tgdavies, Jul 21 '21 at 10:19

score 0 · Answer 1 · answered Apr 04 '22 at 16:27

0

This is an error that occurs when the package name starts with 'java', so it can be resolved by deleting 'java' from the package name.

answered Apr 04 '22 at 16:27

Joo Young Mok

9
1

Your answer could be improved with additional supporting information. Please [edit] to add further details, such as citations or documentation, so that others can confirm that your answer is correct. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Apr 04 '22 at 18:30
This does not really answer the question. If you have a different question, you can ask it by clicking [Ask Question](https://stackoverflow.com/questions/ask). To get notified when this question gets new answers, you can [follow this question](https://meta.stackexchange.com/q/345661). Once you have enough [reputation](https://stackoverflow.com/help/whats-reputation), you can also [add a bounty](https://stackoverflow.com/help/privileges/set-bounties) to draw more attention to this question. - [From Review](/review/late-answers/31455456) – Prasanth Rajendran Apr 06 '22 at 17:55

AppConfig encounter NullPointerException Error

1 Answers1