Scan the classpath in Java: how to scan classes for specific annotations and collect their values

To scan classes for specific annotations and collect their values by using the ClassHunter, we need to initially add the following dependency to our pom.xml:

<dependency>
    <groupId>org.burningwave</groupId>
    <artifactId>core</artifactId>
    <version>12.64.3</version>
</dependency>

… And to use Burningwave Core as a Java module, add the following to your module-info.java:

requires org.burningwave.core;

Let’s take look at the code now:

import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;

import org.burningwave.core.assembler.ComponentContainer;
import org.burningwave.core.assembler.ComponentSupplier;
import org.burningwave.core.classes.ClassCriteria;
import org.burningwave.core.classes.ClassHunter;
import org.burningwave.core.classes.SearchConfig;
import org.burningwave.core.io.PathHelper;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;


public class Finder {

    public List<String> find() {
        ComponentSupplier componentSupplier = ComponentContainer.getInstance();
        PathHelper pathHelper = componentSupplier.getPathHelper();
        ClassHunter classHunter = componentSupplier.getClassHunter();

        SearchConfig searchConfig = SearchConfig.forPaths(
            //Here you can add all absolute path you want:
            //both folders, zip and jar will be recursively scanned.
            //For example you can add: "C:\\Users\\user\\.m2"
            //With the line below the search will be executed on runtime class paths
            pathHelper.getMainClassPaths()
        ).by(
            ClassCriteria.create().allThoseThatMatch((cls) -> {
                return
                    //Unconment one of this if you need to filter for package name
                    //cls.getPackage().getName().matches("regular expression") &&
                    //cls.getPackage().getName().startsWith("com") &&
                    //cls.getPackage().getName().equals("com.something") &&
                    cls.getAnnotation(Controller.class) != null &&
                    cls.getAnnotation(RequestMapping.class) != null;
            })
        );
        try (ClassHunter.SearchResult searchResult = classHunter.findBy(searchConfig)) {
            
            List<String> pathsList = searchResult.getClasses().stream().map(cls -> 
                Arrays.asList(cls.getAnnotation(RequestMapping.class).value())
            ).flatMap(List::stream).distinct().collect(Collectors.toList());
    
            return pathsList;
        }
    }

}