No qualifying bean of type in Spring or Spring Boot

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In this post, we will see about an exception: No qualifying bean of type. Exceptions are least expected but you might get it while working with Spring. or Spring boot.

Did you get this exception: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type?

If yes, let’s see different reasons for it.

Reason 1:
You forgot to declare the bean itself.

Let’s understand this with the help of example.


XML configuration

1. Create a simple java maven project.
2. Maven dependency
put spring and cglib maven dependency in pom.xml.

So your pom.xml will look like:

3. Create Bean class

Create a bean class called X.java in package org.arpit.java2blog .

Please note that we are using Autowired annotation to inject bean y in x.

Create another bean class called Y.java in package org.arpit.java2blog.

4. ApplicationContext.xml
Create ApplicationContext.xml in src/main/resources as below.

We have just declared one bean x here
5. Create SpringApplicationMain.java

6. Run it
When you run above program, you will get below output.

.
.
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.arpit.java2blog.Y] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
.
.

As you can see, we are getting NoSuchBeanDefinitionException: No qualifying bean of type as there is no bean “y” declared in XML.


Java configuration

First 2 steps will remain the same.
let’s add @Component to X.java

Create another bean class called Y.java in package org.arpit.java2blog.

4. Create ApplicationConfiguration.java as below.

5. Create Main class

6. Run it
When you run it, you will get below output.

.
.
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.arpit.java2blog.Y] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
.
.

If you add @Component to Y.java, above exception won’t occur.


Reason 2:
You have not added package name to @ComponentScan.

You might be using @Component,@Service or @Repository but there is no entry for package with @ComponentScan.
For example:
If I change package name to “org.arpit.dummy”, program won’t work,even if you have put @Component with bean Y.



Reason 3:
You have more than one candidate for autowiring

Let’s understand this with the help of example.
Let’s say you one interface named “Decorable”

This interface is implemented by two classes.
CurtianDecorator.java

WallDecorator.java

Create Room.java which will composite reference variable of type interface Decorable.

4. Create ApplicationConfiguration.java as below.

5. Create Main class

6. Run it
When you run it, you will get below output.

.
.
.
Caused by: org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [org.arpit.java2blog.Decorable] is defined: expected single matching bean but found 2: curtianDecorator,wallDecorator
.
.

Please note that this time,we are getting NoUniqueBeanDefinitionException because there are two autowired candidates for Decorable in Room class and spring is not able to resolve which one to use.
You can solve this probem using @Qualifier annotation.

When you run the program again, you will get below output:

Jun 24, 2018 5:19:36 PM org.springframework.context.annotation.AnnotationConfigApplicationContext prepareRefresh
INFO: Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@2e817b38: startup date [Sun Jun 24 17:19:36 IST 2018]; root of context hierarchy
Decorating room with wall decorators

That’s all about no qual

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