use faster gen with JDK methods

terminator-commons/pom.xml

@@ -44,11 +44,6 @@
       <groupId>org.apache.logging.log4j</groupId>
       <artifactId>log4j-core</artifactId>
     </dependency>
-    <dependency>
-      <groupId>io.github.classgraph</groupId>
-      <artifactId>classgraph</artifactId>
-      <version>4.8.162</version>
-    </dependency>
   </dependencies>
 
   <build>

terminator-commons/src/main/java/io/github/algomaster99/terminator/commons/fingerprint/JdkClass.java

@@ -0,0 +1,8 @@
+package io.github.algomaster99.terminator.commons.fingerprint;
+
+import java.nio.ByteBuffer;
+
+/**
+ * A class that represents a JDK class. It contains the name of the class and the bytes of the class as a {@link ByteBuffer}.
+ */
+public record JdkClass(String name, ByteBuffer bytes) {}

terminator-commons/src/main/java/io/github/algomaster99/terminator/commons/fingerprint/JdkIndexer.java

@@ -1,23 +1,53 @@
 package io.github.algomaster99.terminator.commons.fingerprint;
 
-import io.github.classgraph.ClassGraph;
-import io.github.classgraph.Resource;
-import io.github.classgraph.ScanResult;
+import java.lang.module.ModuleFinder;
+import java.lang.module.ModuleReader;
+import java.nio.ByteBuffer;
+import java.util.ArrayList;
 import java.util.List;
-import java.util.stream.Collectors;
+import java.util.Optional;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
+/**
+ * The JdkIndexer class provides a utility to list all JDK classes by scanning the JDK used for the execution of the application.
+ */
 public class JdkIndexer {
 
+    private static final Logger logger = LoggerFactory.getLogger(JdkIndexer.class);
+
     /**
-     * Returns a list of all jdk classes. The list is populated by scanning the jdk used for the execution of this application.
-     * @return a list of all jdk classes, never null.
+     * Returns a list of all JDK classes. The list is populated by scanning the JDK used for the execution of this application.
+     *
+     * @return a list of all JDK classes, never null.
      */
-    public static List<Resource> listJdkClasses() {
-        try (ScanResult scanResult = new ClassGraph()
-                .enableSystemJarsAndModules()
-                .acceptPackages("java.*", "jdk.*", "oracle.*", "sun.*")
-                .scan()) {
-            return scanResult.getAllClasses().stream().map(v -> v.getResource()).collect(Collectors.toList());
-        }
+    public static List<JdkClass> listJdkClasses() {
+        List<JdkClass> jdkClasses = new ArrayList<>();
+        ModuleFinder.ofSystem().findAll().forEach(mr -> {
+            try {
+                try (ModuleReader reader = mr.open()) {
+                    for (String resource : reader.list().toList()) {
+                        if (!resource.endsWith(".class")) {
+                            continue;
+                        }
+                        Optional<ByteBuffer> contents = reader.read(resource);
+                        if (contents.isPresent()) {
+                            jdkClasses.add(new JdkClass(resource, contents.get()));
+                        } else {
+                            logger.atWarn()
+                                    .log(
+                                            "Could not read resource {} from module {}",
+                                            resource,
+                                            mr.descriptor().name());
+                        }
+                    }
+                }
+            } catch (Throwable e) {
+                logger.atError()
+                        .setCause(e)
+                        .log("Error while reading module {}", mr.descriptor().name());
+            }
+        });
+        return jdkClasses;
     }
 }

watchdog-agent/src/main/java/io/github/algomaster99/Options.java

@@ -16,6 +16,7 @@
 import io.github.algomaster99.terminator.commons.jar.JarDownloader;
 import java.io.File;
 import java.io.IOException;
+import java.nio.ByteBuffer;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.security.NoSuchAlgorithmException;
@@ -155,25 +156,34 @@ private void processAllComponents(Bom14Schema sbom) {
     private void processJdk() {
         JdkIndexer.listJdkClasses().forEach(resource -> {
             try {
-
-                byte[] classfileBytes = resource.load();
+                byte[] classfileBytes = toArray(resource.bytes());
                 ClassReader classReader = new ClassReader(classfileBytes);
-
                 String classfileVersion = ClassfileVersion.getVersion(classfileBytes);
                 String hash = HashComputer.computeHash(classfileBytes, algorithm);
                 jdkFingerprints.put(
                         classReader.getClassName(),
                         List.of(new Jdk(new ClassFileAttributes(classfileVersion, hash, algorithm))));
-            } catch (IOException e) {
-                LOGGER.error("Failed to load classfile bytes for: " + resource, e);
-                throw new RuntimeException(e);
             } catch (NoSuchAlgorithmException e) {
                 LOGGER.error("Failed to compute hash with algorithm: " + algorithm, e);
                 throw new RuntimeException(e);
             } catch (Exception e) {
                 LOGGER.error("Failed to compute hash for: " + resource, e);
-                System.out.println("Failed to compute hash for: " + resource.getPath());
             }
         });
     }
+
+    /**
+     * Converts a bytebuffer to a byte array. If the buffer has an array, it returns it, otherwise it copies the bytes. This is needed because the buffer is not guaranteed to have an array.
+     * See {@link java.nio.ByteBuffer#hasArray()} and {@link java.nio.DirectByteBuffer}.
+     * @param buffer  the buffer to convert
+     * @return  the byte array
+     */
+    private byte[] toArray(ByteBuffer buffer) {
+        if (buffer.hasArray()) {
+            return buffer.array();
+        }
+        byte[] bytes = new byte[buffer.remaining()];
+        buffer.get(bytes);
+        return bytes;
+    }
 }