Migrated project to Java 17 and use JavaDowngrader gradle plugin to target Java 8

build.gradle

@@ -1,25 +1,37 @@
+import net.raphimc.javadowngrader.gradle.task.DowngradeJarTask
+
+buildscript {
+    repositories {
+        maven {
+            name = "Lenni0451 Releases"
+            url "https://maven.lenni0451.net/releases"
+        }
+        maven {
+            name = "Lenni0451 Snapshots"
+            url "https://maven.lenni0451.net/snapshots"
+        }
+    }
+
+    dependencies {
+        classpath "net.raphimc.javadowngrader:gradle-plugin:1.0.0"
+    }
+}
+
 plugins {
     id "java"
     id "application"
     id "maven-publish"
-    id "net.kyori.blossom" version "2.0.1"
+    id "net.kyori.blossom" version "1.3.1"
 }
 
-sourceSets {
+base {
-    java17compat
+    java.toolchain.languageVersion = JavaLanguageVersion.of(17)
-}
+    compileJava.options.encoding = compileTestJava.options.encoding = javadoc.options.encoding = "UTF-8"
 
-java.toolchain.languageVersion = JavaLanguageVersion.of(17)
+    group = project.maven_group ?: rootProject.maven_group
-[compileJava, compileTestJava, compileJava17compatJava].each {
+    archivesName = project.maven_name ?: rootProject.maven_name
-    it.options.encoding = "UTF-8"
+    version = project.maven_version ?: rootProject.maven_version
-    it.sourceCompatibility = JavaVersion.VERSION_1_8
-    it.targetCompatibility = JavaVersion.VERSION_1_8
 }
-javadoc.options.encoding = "UTF-8"
-
-group = project.maven_group
-archivesBaseName = project.maven_name
-version = project.maven_version
 
 configurations {
     include
@@ -35,7 +47,7 @@ repositories {
         url = "https://jitpack.io"
     }
     maven {
-        name = "Lenni0451"
+        name = "Lenni0451 Releases"
         url "https://maven.lenni0451.net/releases"
     }
     maven {
@@ -58,24 +70,9 @@ repositories {
         name = "Minecraft Libraries"
         url "https://libraries.minecraft.net"
     }
-    ivy { // This workaround is needed as gradle does not allow to include Java 17 dependencies in a Java 8 project
-        name = "Mojang"
-        url "https://libraries.minecraft.net"
-        patternLayout {
-            artifact MAVEN_ARTIFACT_PATTERN
-        }
-        metadataSources {
-            it.artifact()
-        }
-        content {
-            includeGroup "com/mojang"
-        }
-    }
 }
 
 dependencies {
-    compileOnly sourceSets.java17compat.output
-
     include "com.viaversion:viaversion:4.8.0-23w35a-SNAPSHOT"
     include("com.viaversion:viabackwards-common:4.8.0-23w35a-SNAPSHOT") {
         exclude group: "com.viaversion", module: "viaversion"
@@ -102,10 +99,12 @@ dependencies {
     include "net.sf.jopt-simple:jopt-simple:5.0.4"
     include "org.apache.logging.log4j:log4j-core:2.20.0"
     include "org.apache.logging.log4j:log4j-slf4j-impl:2.20.0"
-    include "com/mojang:authlib:3.16.29"
+    include("com.mojang:authlib:3.16.29") {
-    include "net.lenni0451.classtransform:mixinstranslator:1.10.1"
+        exclude group: "org.slf4j", module: "slf4j-api"
-    include "net.lenni0451.classtransform:mixinsdummy:1.10.1"
+    }
-    include "net.lenni0451.classtransform:additionalclassprovider:1.10.1"
+    include "net.lenni0451.classtransform:mixinstranslator:1.11.0-SNAPSHOT"
+    include "net.lenni0451.classtransform:mixinsdummy:1.11.0-SNAPSHOT"
+    include "net.lenni0451.classtransform:additionalclassprovider:1.11.0-SNAPSHOT"
     include "net.lenni0451:Reflect:1.2.4"
     include "net.lenni0451:LambdaEvents:2.2.0"
     include "net.raphimc.netminecraft:all:2.3.6-SNAPSHOT"
@@ -113,9 +112,9 @@ dependencies {
         exclude group: "com.google.code.gson", module: "gson"
         exclude group: "org.slf4j", module: "slf4j-api"
     }
-    include("net.raphimc.javadowngrader:core:1.0.0-SNAPSHOT") {
+    include("net.raphimc.javadowngrader:impl-classtransform:1.0.0") {
-        exclude group: "org.slf4j", module: "slf4j-api"
         exclude group: "org.ow2.asm", module: "asm-commons"
+        exclude group: "net.lenni0451.classtransform", module: "core"
     }
     include("org.cloudburstmc.netty:netty-transport-raknet:1.0.0.CR1-SNAPSHOT") {
         exclude group: "io.netty", module: "netty-common"
@@ -153,12 +152,12 @@ jar {
         attributes(
                 "Main-Class": application.mainClass,
                 "Multi-Release": "true",
-                "Launcher-Agent-Class": "net.raphimc.viaproxy.ViaProxy"
+                "Launcher-Agent-Class": application.mainClass
         )
     }
 
     from("LICENSE") {
-        rename { "${it}_${project.archivesBaseName}" }
+        rename { "${it}_${project.name ?: rootProject.name}" }
     }
 }
 
@@ -206,3 +205,11 @@ publishing {
         }
     }
 }
+
+tasks.register("java8Jar", DowngradeJarTask) {
+    input = tasks.jar.archiveFile.get().asFile
+    outputSuffix = "+java8"
+    compileClassPath = sourceSets.main.compileClasspath
+    copyRuntimeClasses = false
+}.get().dependsOn("build")
+build.finalizedBy("java8Jar")

gradle.properties

@@ -1,9 +1,7 @@
-# Gradle properties
 org.gradle.daemon=true
 org.gradle.parallel=true
 org.gradle.configureondemand=true
 
-# Project properties
-maven_name=ViaProxy
 maven_group=net.raphimc
+maven_name=ViaProxy
 maven_version=3.0.21-SNAPSHOT

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.5.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.3-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

src/java17compat/java/java/lang/Record.java

@@ -1,37 +0,0 @@
-/*
- * This file is part of ViaProxy - https://github.com/RaphiMC/ViaProxy
- * Copyright (C) 2023 RK_01/RaphiMC and contributors
- *
- * This program is free software: you can redistribute it and/or modify
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program.  If not, see <http://www.gnu.org/licenses/>.
- */
-package java.lang;
-
-/**
- * Dummy class to make IntelliJ able to access records in Java 8 code.
- */
-public abstract class Record {
-
-    protected Record() {
-    }
-
-    @Override
-    public abstract boolean equals(Object obj);
-
-    @Override
-    public abstract int hashCode();
-
-    @Override
-    public abstract String toString();
-
-}

src/main/java/net/raphimc/viaproxy/ViaProxy.java

@@ -35,7 +35,6 @@ import net.raphimc.netminecraft.constants.MCPipeline;
 import net.raphimc.netminecraft.netty.connection.NetServer;
 import net.raphimc.viaproxy.cli.ConsoleHandler;
 import net.raphimc.viaproxy.cli.options.Options;
-import net.raphimc.viaproxy.injection.Java17ToJava8;
 import net.raphimc.viaproxy.plugins.PluginManager;
 import net.raphimc.viaproxy.plugins.events.Client2ProxyHandlerCreationEvent;
 import net.raphimc.viaproxy.plugins.events.ProxyStartEvent;
@@ -74,7 +73,6 @@ public class ViaProxy {
         final IClassProvider classProvider = new GuavaClassPathProvider();
         final TransformerManager transformerManager = new TransformerManager(classProvider);
         transformerManager.addTransformerPreprocessor(new MixinsTranslator());
-        transformerManager.addBytecodeTransformer(new Java17ToJava8(transformerManager).addWhitelistedPackage("com.mojang"));
         transformerManager.addTransformer("net.raphimc.viaproxy.injection.transformer.**");
         transformerManager.addTransformer("net.raphimc.viaproxy.injection.mixins.**");
         if (instrumentation != null) {
@@ -103,6 +101,14 @@ public class ViaProxy {
         Logger.LOGGER.info("Available memory (bytes): " + Runtime.getRuntime().maxMemory());
 
         if (System.getProperty("ignoreSystemRequirements") == null) {
+            if ("32".equals(System.getProperty("sun.arch.data.model")) && Runtime.getRuntime().maxMemory() < 256 * 1024 * 1024) {
+                Logger.LOGGER.fatal("ViaProxy is not able to run on 32bit Java.");
+                if (hasUI) {
+                    JOptionPane.showMessageDialog(null, "ViaProxy is not able to run on 32bit Java. Please install 64bit Java", "ViaProxy", JOptionPane.ERROR_MESSAGE);
+                }
+                System.exit(1);
+            }
+
             if (Runtime.getRuntime().maxMemory() < 256 * 1024 * 1024) {
                 Logger.LOGGER.fatal("ViaProxy is not able to run with less than 256MB of RAM.");
                 if (hasUI) {

src/main/java/net/raphimc/viaproxy/injection/Java17ToJava8.java

@@ -19,68 +19,21 @@ package net.raphimc.viaproxy.injection;
 
 import net.lenni0451.classtransform.TransformerManager;
 import net.lenni0451.classtransform.transformer.IBytecodeTransformer;
-import net.lenni0451.classtransform.utils.ASMUtils;
-import net.lenni0451.classtransform.utils.tree.ClassTree;
-import net.lenni0451.classtransform.utils.tree.IClassProvider;
-import net.raphimc.javadowngrader.JavaDowngrader;
-import org.objectweb.asm.tree.ClassNode;
-
-import java.nio.ByteBuffer;
-import java.util.ArrayList;
-import java.util.List;
 
+/**
+ * This class should not be used anymore. ViaProxy does now automatically downgrade all plugins to the current java version.
+ */
+@Deprecated
 public class Java17ToJava8 implements IBytecodeTransformer {
 
-    private final ClassTree classTree;
+    @Deprecated
-    private final IClassProvider classProvider;
-    private final int nativeClassVersion;
-    private final List<String> whitelistedPackages = new ArrayList<>();
-
-    public Java17ToJava8(final ClassTree classTree, final IClassProvider classProvider) {
-        this.classTree = classTree;
-        this.classProvider = classProvider;
-
-        final String classVersion = System.getProperty("java.class.version");
-        final String[] versions = classVersion.split("\\.");
-        final int majorVersion = Integer.parseInt(versions[0]);
-        final int minorVersion = Integer.parseInt(versions[1]);
-        this.nativeClassVersion = minorVersion << 16 | majorVersion;
-    }
-
     public Java17ToJava8(final TransformerManager transformerManager) {
-        this(transformerManager.getClassTree(), transformerManager.getClassProvider());
-    }
-
-    public Java17ToJava8 addWhitelistedPackage(final String packageName) {
-        this.whitelistedPackages.add(packageName);
-        return this;
     }
 
+    @Deprecated
     @Override
-    public byte[] transform(final String className, final byte[] bytecode, final boolean calculateStackMapFrames) {
+    public byte[] transform(String className, byte[] bytecode, boolean calculateStackMapFrames) {
-        if (ByteBuffer.wrap(bytecode, 4, 4).getInt() <= this.nativeClassVersion) {
+        return null;
-            return null;
-        }
-
-        if (!this.whitelistedPackages.isEmpty()) {
-            int dotIndex = className.lastIndexOf('.');
-            if (dotIndex == -1 && !this.whitelistedPackages.contains("")) return null;
-            String pkg = className.substring(0, dotIndex);
-            while (!this.whitelistedPackages.contains(pkg)) {
-                dotIndex = pkg.lastIndexOf('.');
-                if (dotIndex == -1) return null;
-                pkg = pkg.substring(0, dotIndex);
-            }
-        }
-
-        final ClassNode classNode = ASMUtils.fromBytes(bytecode);
-        JavaDowngrader.downgrade(classNode, this.nativeClassVersion);
-
-        if (calculateStackMapFrames) {
-            return ASMUtils.toBytes(classNode, this.classTree, this.classProvider);
-        } else {
-            return ASMUtils.toStacklessBytes(classNode);
-        }
     }
 
 }

src/main/java/net/raphimc/viaproxy/plugins/PluginManager.java

@@ -25,6 +25,7 @@ import net.lenni0451.classtransform.utils.tree.IClassProvider;
 import net.lenni0451.lambdaevents.LambdaManager;
 import net.lenni0451.lambdaevents.generator.LambdaMetaFactoryGenerator;
 import net.lenni0451.reflect.stream.RStream;
+import net.raphimc.javadowngrader.impl.classtransform.JavaDowngraderTransformer;
 import net.raphimc.viaproxy.ViaProxy;
 import net.raphimc.viaproxy.util.URLClassProvider;
 import net.raphimc.viaproxy.util.logging.Logger;
@@ -90,6 +91,7 @@ public class PluginManager {
     private static void loadAndScanJar(final File file) throws Throwable {
         final URL url = file.toURI().toURL();
         final TransformerManager transformerManager = new TransformerManager(new URLClassProvider(ROOT_CLASS_PROVIDER, url));
+        transformerManager.addBytecodeTransformer(new JavaDowngraderTransformer(transformerManager));
         final InjectionClassLoader loader = new InjectionClassLoader(transformerManager, PluginManager.class.getClassLoader(), url);
         final InputStream viaproxyYml = loader.getResourceAsStream("viaproxy.yml");
         if (viaproxyYml == null) throw new IllegalStateException("Plugin '" + file.getName() + "' does not have a viaproxy.yml");

src/main/java/net/raphimc/viaproxy/tasks/UpdateCheckTask.java

@@ -75,11 +75,12 @@ public class UpdateCheckTask implements Runnable {
             if (updateAvailable) {
                 Logger.LOGGER.warn("You are running an outdated version of ViaProxy! Latest version: " + latestVersion);
                 if (this.hasUI) {
+                    final boolean runsJava8 = System.getProperty("java.version").startsWith("1.8");
                     JsonArray assets = object.getAsJsonArray("assets");
                     boolean found = false;
                     for (JsonElement asset : assets) {
                         JsonObject assetObject = asset.getAsJsonObject();
-                        if (this.isViaProxyJar(object, assetObject)) {
+                        if ((this.isMainViaProxyJar(object, assetObject) && !runsJava8) || this.isJava8ViaProxyJar(object, assetObject) && runsJava8) {
                             found = true;
                             SwingUtilities.invokeLater(() -> this.showUpdateQuestion(assetObject.get("name").getAsString(), assetObject.get("browser_download_url").getAsString(), latestVersion));
                             break;
@@ -100,18 +101,16 @@ public class UpdateCheckTask implements Runnable {
         int chosen = JOptionPane.showConfirmDialog(ViaProxy.ui, "You are running an outdated version of ViaProxy!\nCurrent version: " + VERSION + "\nLatest version: " + latestVersion + "\n\nDo you want to update?", "ViaProxy", JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE);
         if (chosen == JOptionPane.YES_OPTION) {
             File f = new File(name);
-            new DownloadPopup(ViaProxy.ui, downloadUrl, f, () -> {
+            new DownloadPopup(ViaProxy.ui, downloadUrl, f, () -> SwingUtilities.invokeLater(() -> {
-                SwingUtilities.invokeLater(() -> {
+                JOptionPane.showMessageDialog(ViaProxy.ui, "Downloaded the latest version of ViaProxy!\nPress OK to restart.", "ViaProxy", JOptionPane.INFORMATION_MESSAGE);
-                    JOptionPane.showMessageDialog(ViaProxy.ui, "Downloaded the latest version of ViaProxy!\nPress OK to restart.", "ViaProxy", JOptionPane.INFORMATION_MESSAGE);
+                try {
-                    try {
+                    Runtime.getRuntime().exec(new String[]{System.getProperty("java.home") + "/bin/java", "-jar", f.getAbsolutePath()});
-                        Runtime.getRuntime().exec(new String[]{System.getProperty("java.home") + "/bin/java", "-jar", f.getAbsolutePath()});
+                    System.exit(0);
-                        System.exit(0);
+                } catch (IOException e) {
-                    } catch (IOException e) {
+                    Logger.LOGGER.error("Could not start the new ViaProxy jar", e);
-                        Logger.LOGGER.error("Could not start the new ViaProxy jar", e);
+                    ViaProxy.ui.showException(e);
-                        ViaProxy.ui.showException(e);
+                }
-                    }
+            }), t -> {
-                });
-            }, t -> {
                 if (t != null) {
                     Logger.LOGGER.error("Could not download the latest version of ViaProxy", t);
                     ViaProxy.ui.showException(t);
@@ -120,8 +119,12 @@ public class UpdateCheckTask implements Runnable {
         }
     }
 
-    private boolean isViaProxyJar(final JsonObject root, final JsonObject assetObject) {
+    private boolean isMainViaProxyJar(final JsonObject root, final JsonObject assetObject) {
         return assetObject.get("name").getAsString().equals(root.get("name").getAsString() + ".jar");
     }
 
+    private boolean isJava8ViaProxyJar(final JsonObject root, final JsonObject assetObject) {
+        return assetObject.get("name").getAsString().equals(root.get("name").getAsString() + "+java8.jar");
+    }
+
 }