support JDK 21

.github/workflows/build-and-release.yml

@@ -144,7 +144,7 @@ jobs:
         uses: actions/setup-java@v4
         with:
           distribution: 'temurin'
-          java-version: '17'
+          java-version: '21'
           cache: 'maven'
 
       - name: Build with Maven

README.md

@@ -38,7 +38,7 @@ Support the project with XDAG donations:
 
 ### **1. Requirements**
 
-- **JDK**: v17 or later
+- **JDK**: v21 or later
 - **Maven**: v3.9.9 or later
 - **CMake**: v3.5 or later
 - **GCC/Compiler**: GCC v4.8 or later (v7+ recommended for best performance)
@@ -115,7 +115,7 @@ To include `xdagj-native-randomx` in your project, add the following dependency
 <dependency>
     <groupId>io.xdag</groupId>
     <artifactId>xdagj-native-randomx</artifactId>
-    <version>0.2.3</version>
+    <version>0.2.4</version>
 </dependency>
 ```
 

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>io.xdag</groupId>
     <artifactId>xdagj-native-randomx</artifactId>
-    <version>0.2.3</version>
+    <version>0.2.4</version>
 
     <name>xdagj-native-randomx</name>
     <description>A Java RandomX Library For XDAGJ</description>
@@ -17,8 +17,8 @@
         <!-- Build properties -->
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <maven.compiler.encoding>UTF-8</maven.compiler.encoding>
-        <maven.compiler.source>17</maven.compiler.source>
-        <maven.compiler.target>17</maven.compiler.target>
+        <maven.compiler.source>21</maven.compiler.source>
+        <maven.compiler.target>21</maven.compiler.target>
 
         <!-- Dependency versions -->
         <commons-lang3.version>3.17.0</commons-lang3.version>
@@ -81,6 +81,14 @@
                 <configuration>
                     <source>${maven.compiler.source}</source>
                     <target>${maven.compiler.target}</target>
+                    <annotationProcessorPaths>
+                        <path>
+                            <groupId>org.projectlombok</groupId>
+                            <artifactId>lombok</artifactId>
+                            <version>${lombok.version}</version>
+                        </path>
+                        <!-- Add other annotation processors if needed -->
+                    </annotationProcessorPaths>
                 </configuration>
             </plugin>
 
@@ -91,6 +99,7 @@
                 <configuration>
                     <redirectTestOutputToFile>true</redirectTestOutputToFile>
                     <printSummary>true</printSummary>
+                    <argLine>--enable-preview</argLine>
                 </configuration>
             </plugin>
 
@@ -151,6 +160,9 @@
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-javadoc-plugin</artifactId>
                 <version>${maven-javadoc-plugin.version}</version>
+                <configuration>
+                    <source>${maven.compiler.source}</source>
+                </configuration>
                 <executions>
                     <execution>
                         <id>attach-javadocs</id>

src/main/java/io/xdag/crypto/randomx/Example.java

@@ -33,6 +33,15 @@
  */
 public class Example {
 
+    /**
+     * Default constructor for the Example class.
+     * This constructor is intentionally empty as this class primarily serves as a demonstration
+     * with static methods or through its main method.
+     */
+    public Example() {
+        // Default constructor
+    }
+
     /**
      * Main method demonstrating the RandomX hashing process.
      * Shows initialization of RandomX components and hash calculation.

src/main/java/io/xdag/crypto/randomx/RandomXFlag.java

@@ -117,7 +117,7 @@ public enum RandomXFlag {
      * Each bit in the input value corresponds to a specific flag.
      *
      * @param flags The combined integer value of multiple flags
-     * @return A set of RandomXFlag enums corresponding to the enabled bits
+     * @return A set of RandomXFlag enums corresponding to the enabled bits.
      */
     public static Set<RandomXFlag> fromValue(int flags) {
         EnumSet<RandomXFlag> result = EnumSet.noneOf(RandomXFlag.class);

src/main/java/io/xdag/crypto/randomx/RandomXLibraryLoader.java

@@ -40,7 +40,7 @@
 final class RandomXLibraryLoader {
 
     private static boolean isLoaded = false;
-    private static String loadedLibraryPath = null; // Store the path of the loaded library for logging
+    private static Path loadedLibraryPath = null; // Store the path of the loaded library
 
     // Private constructor to prevent instantiation
     private RandomXLibraryLoader() {}
@@ -53,16 +53,19 @@ private RandomXLibraryLoader() {}
      *
      * @throws UnsatisfiedLinkError if the library cannot be loaded for any reason.
      * @throws Exception for other unexpected errors during loading.
+     * @return Path to the loaded native library file, or null if already loaded or failed before critical point.
      */
-    public static synchronized void load() throws Exception {
+    public static synchronized Path load() throws Exception {
         if (isLoaded) {
             log.info("Native library already loaded from: {}", loadedLibraryPath);
-            return;
+            return loadedLibraryPath; // Return cached path
         }
 
+        Path tempLibFilePath = null;
         try {
-            File tempFile = extractAndLoadNativeLibrary();
-            loadedLibraryPath = tempFile.getAbsolutePath();
+            File tempFile = extractAndLoadNativeLibrary(); // This method now returns File
+            tempLibFilePath = tempFile.toPath();
+            loadedLibraryPath = tempLibFilePath; // Cache the path
 
             String tempLibDir = tempFile.getParent();
             if (tempLibDir != null) {
@@ -79,10 +82,12 @@ public static synchronized void load() throws Exception {
 
             isLoaded = true;
             log.info("RandomX native library loaded successfully via RandomXLibraryLoader from: {}", loadedLibraryPath);
+            return loadedLibraryPath;
 
         } catch (UnsatisfiedLinkError ule) { // Catch specifically from System.load()
             log.error("Failed to load native library (UnsatisfiedLinkError from System.load()): {}: {}", 
-                     (loadedLibraryPath != null ? loadedLibraryPath : "<path not determined>"), ule.getMessage(), ule);
+                     (loadedLibraryPath != null ? loadedLibraryPath : (tempLibFilePath != null ? tempLibFilePath : "<path not determined>")), 
+                     ule.getMessage(), ule);
             logLibraryPaths(); // Log paths for diagnostics
             throw ule; // Re-throw to be handled by RandomXNative's static block
         } catch (Exception e) {

src/main/java/io/xdag/crypto/randomx/RandomXNative.java

@@ -33,6 +33,14 @@
  * This class registers the native methods after the library is successfully loaded.
  */
 public class RandomXNative {
+    /**
+     * Private constructor to prevent instantiation.
+     * This class provides static JNA mappings and should not be instantiated.
+     */
+    private RandomXNative() {
+        throw new UnsupportedOperationException("This is a JNA mapping class and cannot be instantiated");
+    }
+
     static {
         try {
             // Step 1: Initialize the library using the loader.

src/main/java/io/xdag/crypto/randomx/RandomXTemplate.java

@@ -38,6 +38,19 @@
 @ToString
 @Slf4j
 public class RandomXTemplate implements AutoCloseable {
+    /**
+     * Private constructor to be used by the Lombok generated builder.
+     * Direct instantiation is discouraged; use the builder pattern.
+     */
+    private RandomXTemplate(boolean miningMode, Set<RandomXFlag> flags, RandomXCache cache, RandomXDataset dataset, RandomXVM vm, byte[] currentKey) {
+        this.miningMode = miningMode;
+        this.flags = flags;
+        this.cache = cache;
+        this.dataset = dataset;
+        this.vm = vm;
+        this.currentKey = currentKey;
+    }
+
     /** Flag indicating if the template is in mining mode */
     @Getter
     private final boolean miningMode;

src/main/java/io/xdag/crypto/randomx/RandomXUtils.java

@@ -33,6 +33,13 @@
  */
 public final class RandomXUtils {
 
+    /**
+     * Private constructor to prevent instantiation of this utility class.
+     */
+    private RandomXUtils() {
+        throw new UnsupportedOperationException("This is a utility class and cannot be instantiated");
+    }
+
     /**
      * The size of a RandomX hash in bytes (usually 32 bytes).
      */