Java file outside of source root

When a Java file is placed outside of the source root, it means that the file is not located within the directory structure that the Java compiler and runtime expect by default. This situation may arise if the file is accidentally moved or copied to a different location, or if you are working with a non-standard project setup.

To understand this better, let’s consider an example:

Suppose you have a Java project with the following directory structure:

  
    project/
    └── src/
        ├── main/
        │   └── java/
        │       └── com/
        │           └── example/
        │               └── MyClass.java
        └── test/
            └── java/
                └── com/
                    └── example/
                        └── TestClass.java
  
  

In this case, the source root is the “src/main/java” directory. Both “MyClass.java” and “TestClass.java” are located within this source root, so they can be compiled and run without any issues.

Now, let’s say you accidentally move “TestClass.java” outside of the source root and place it in the project directory:

  
    project/
    ├── src/
    │   ├── main/
    │   │   └── java/
    │   │       └── com/
    │   │           └── example/
    │   │               └── MyClass.java
    │   └── test/
    │       └── java/
    │           └── com/
    │               └── example/
    └── TestClass.java
  
  

Now, when you try to compile and run “TestClass.java”, you will encounter an error. The Java compiler and runtime expect the file to be located within the source root, so it cannot find the class files and dependencies.

To fix this issue, you need to move “TestClass.java” back to its original location within the source root:

  
    project/
    ├── src/
    │   ├── main/
    │   │   └── java/
    │   │       └── com/
    │   │           └── example/
    │   │               └── MyClass.java
    │   └── test/
    │       └── java/
    │           └── com/
    │               └── example/
    │                   └── TestClass.java
  
  

Now, you should be able to compile and run “TestClass.java” without any issues.

In conclusion, placing a Java file outside of the source root can cause compilation and runtime errors. It is important to ensure that all Java files are located within the expected directory structure to avoid such issues.