How to fix org.springframework.beans.factory.BeanCreationException: Error creating bean with name X [Java Spring]

If you are using the Spring framework in your Java application and getting this error during startup it means Spring is not able to initialize the bean X and add it into its application context, Why? There could be multiple reasons like a typo on the spring bean name. Let's take a closer look at the stack trace to find out the real reason:

BeanInstantiationException: Could not instantiate bean class [X]: No default constructor found; nested exception is java.lang.NoSuchMethodException: X.()

Here X is the class, which is declared as Spring bean. The error clearly says that the default constructor is not present in class X.

By default, Spring will try to instantiate beans by calling the default or no-argument constructor and if it doesn't find the default, no-argument constructor then it is not able to initialize the bean and hence it throws the BeanInstantiationException during startup, the real reason is also appended into stack trace as NoSuchMethodException.

If you remember, Java by default adds a default constructor in every class but many programmers don't know that it only does that if you don't have any constructor in the class if by any chance you have defined a constructor which takes a parameter, then Java will not add it.

This is also one of the reasons I suggest always add a default constructor in the Java class, no matter whether you have more constructors or not. Java allows constructor overloading and you should take advantage of that.

I also suggest you go through a comprehensive Spring online training course to understand how Spring works, how it instantiates objects, where does it keep the object reference, dependency injection, IOC container, and much more.

If you need a recommendation then I suggest you join one of the courses in this list of best Spring courses for Java developers. It's one of the most up-to-date resources to learn in Spring and covers Spring 5.0 and Reactive Programming as well. 

How to solve Error creating bean with name X [Java Spring]

Now, it depends on how you are instructing Spring to instantiate your bean? If you are using auto-wiring like @Autowired annotation, and you also have a suitable constructor define then just annotated that with @Autwired annotation, as shown below:

public class X{
private D d;

@Autowired
public X(Y dependency){
this.d = depenency;
}

}

Your problem will be solved.

Btw, if you are using XML based configuration then make sure you are using the right constructor on your config.

Also, as per Spring Java documentation, A BeanCrationException is thrown when a BeanFactory encounters an error while attempting to create a bean from bean definition. It doesn't say anything about the error, that's why you need to look at the nested exception to find the actual cause.

For example, in this case, the nested error was BeanInstantiationException, which indicates the instantiation of a bean failed.

You should always pay attention to detailed stack trace as It also carries the offending bean class and reason like in this case, it was trying to instantiate bean by invoking default constructor and couldn't find it.

By looking at the error, you can conclude that whether you need to add a default constructor or Spring is invoking a wrong constructor, which means a missing config somehow.

Sometimes BeanInstantiationException is also throwing in Spring is not able to find the bean class in the classpath. That time you will see either NoClassDefFoundError or ClassNotFoundException as a nested exception in the stack trace.

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Thanks for reading this article so far. If you like this troubleshooting guide and my explanation of Spring's BeanCreationException then please share it with your friends and colleagues. If you have any questions or feedback, please drop a comment.

P.S. -  If you are a beginner and looking for a free online course to cover gaps in your learning or just want to learn the Spring framework from scratch then you can also check out these free Spring Courses For Beginners from Udemy and Coursera. It's completely free and you just need a free Udemy account to enroll in this course.