Consider the following dependency hierarchy:
Now I have maven-jibx-plugin in project D which generates the compiled classes in target/classes folder. But when I run my spring-boot project A the generated classes from project D could not be resolved.
Resolve dependencies from workspace is also checked from maven preferences of project A

To me it looks like Eclipse and Maven do not recognize project D as a related project.
There are two possible solutions:
In Eclipse you can add project D as a dependent project to project A's build path. Go to the project's Properties dialog. Select Java Build Path and then switch to the Projects tab. There you should add project D.
Or alternatively you rely on Maven's dependency management. Therefore you have to add a dependency to project A's POM file. First add a
<dependency>( if not already done ) to the<dependencies>section. Now comes the important part! Maven can only resolve this dependency if you have installed the compiled maven artifact ( the jar file ) in your local maven repository. On the shell switch into project D's directory and then runmvn installI hope that did the trick.