Provide an example of using custom tags in Java.

Custom tags in Java are typically used in the context of generating documentation with Javadoc. They allow adding additional information to code elements (classes, methods, fields, etc.), which will be included in the generated documentation.

Example of creating and using a custom @todo tag:

Declaring the tag in the overview.html file or in the Doclet configuration:

If using the standard Doclet, the tag needs to be declared. This can be done, for example, in the overview.html file, which is used for describing the overall project overview.
```
<body>
This project is intended to demonstrate custom Javadoc tags.
<br>
<b>Additional tags:</b><br>
<code>@todo</code> - Description of the task or action to be performed.
</body>
```
Or when running javadoc with the -tag option:
```
javadoc -tag "todo:a:Tasks" MyClass.java
```
where "a" indicates that the tag applies to all elements (classes, methods, fields).

Using the tag in Java code:

/**
 * This class demonstrates the use of a custom `@todo` tag.
 * <p>
 * {@todo Add more detailed description of the class functionality}
 */
public class MyClass {

    /**
     * Main method of the class.
     * {@todo Implement input data processing logic}
     */
    public void processData() {
        // TODO: Do something
    }

    /**
     * Helper method.
     * {@todo Refactor this method after completing the main logic}
     */
    private void helperMethod() {
        // Helper code
    }
}

Generating documentation:

Run the javadoc utility with the specified options and source files. For example:
```
javadoc -tag "todo:a:Tasks" MyClass.java
```
or, if using overview.html:
```
javadoc -overview overview.html MyClass.java
```

The generated HTML documentation will include a new section or line for each element with the @todo tag and its description.