feature: Support JDK21 (and drop JDK7 support)

.github/workflows/CI.yml

@@ -27,6 +27,24 @@ jobs:
       - uses: actions/checkout@v2
       - name: jcheckstyle
         run: ./sbt jcheckStyle
+  test_jdk21:
+    name: Test JDK21
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-java@v3
+        with:
+          distribution: 'zulu'
+          java-version: '21'
+      - uses: actions/cache@v2
+        with:
+          path: ~/.cache
+          key: ${{ runner.os }}-jdk21-${{ hashFiles('**/*.sbt') }}
+          restore-keys: ${{ runner.os }}-jdk21-
+      - name: Test
+        run: ./sbt test
+      - name: Universal Buffer Test
+        run: ./sbt test -J-Dmsgpack.universal-buffer=true
   test_jdk17:
     name: Test JDK17
     runs-on: ubuntu-latest
@@ -39,7 +57,7 @@ jobs:
       - uses: actions/cache@v2
         with:
           path: ~/.cache
-          key: ${{ runner.os }}-jdk11-${{ hashFiles('**/*.sbt') }}
+          key: ${{ runner.os }}-jdk17-${{ hashFiles('**/*.sbt') }}
           restore-keys: ${{ runner.os }}-jdk17-
       - name: Test
         run: ./sbt test

build.sbt

@@ -17,7 +17,7 @@ val buildSettings = Seq[Setting[_]](
   organizationName := "MessagePack",
   organizationHomepage := Some(new URL("http://msgpack.org/")),
   description := "MessagePack for Java",
-  scalaVersion := "2.13.6",
+  scalaVersion := "2.13.12",
   Test / logBuffered := false,
   // msgpack-java should be a pure-java library, so remove Scala specific configurations
   autoScalaLibrary := false,
@@ -26,11 +26,11 @@ val buildSettings = Seq[Setting[_]](
   // JVM options for building
   scalacOptions ++= Seq("-encoding", "UTF-8", "-deprecation", "-unchecked", "-feature"),
   Test / javaOptions ++= Seq("-ea"),
-  javacOptions ++= Seq("-source", "1.7", "-target", "1.7"),
+  javacOptions ++= Seq("-source", "1.8", "-target", "1.8"),
   Compile / compile / javacOptions ++= Seq("-encoding", "UTF-8", "-Xlint:unchecked", "-Xlint:deprecation"),
   // Use lenient validation mode when generating Javadoc (for Java8)
   doc / javacOptions := {
-    val opts = Seq("-source", "1.7")
+    val opts = Seq("-source", "1.8")
     if (scala.util.Properties.isJavaAtLeast("1.8")) {
       opts ++ Seq("-Xdoclint:none")
     } else {
@@ -92,7 +92,7 @@ lazy val msgpackCore = Project(id = "msgpack-core", base = file("msgpack-core"))
       "org.msgpack" % "msgpack" % "0.6.12" % "test",
       // For integration test with Akka
       "com.typesafe.akka"      %% "akka-actor"              % "2.6.20" % "test",
-      "org.scala-lang.modules" %% "scala-collection-compat" % "2.11.0"  % "test"
+      "org.scala-lang.modules" %% "scala-collection-compat" % "2.11.0" % "test"
     )
   )
 

msgpack-core/src/main/java/org/msgpack/core/buffer/DirectBufferAccess.java

@@ -37,6 +37,7 @@ private DirectBufferAccess()
 
     enum DirectBufferConstructorType
     {
+        ARGS_LONG_LONG,
         ARGS_LONG_INT_REF,
         ARGS_LONG_INT,
         ARGS_INT_INT,
@@ -64,28 +65,35 @@ enum DirectBufferConstructorType
             DirectBufferConstructorType constructorType = null;
             Method mbWrap = null;
             try {
-                // TODO We should use MethodHandle for Java7, which can avoid the cost of boxing with JIT optimization
-                directByteBufferConstructor = directByteBufferClass.getDeclaredConstructor(long.class, int.class, Object.class);
-                constructorType = DirectBufferConstructorType.ARGS_LONG_INT_REF;
+                // JDK21 DirectByteBuffer(long, long)
+                directByteBufferConstructor = directByteBufferClass.getDeclaredConstructor(long.class, long.class);
+                constructorType = DirectBufferConstructorType.ARGS_LONG_LONG;
             }
-            catch (NoSuchMethodException e0) {
+            catch (NoSuchMethodException e00) {
                 try {
-                    // https://android.googlesource.com/platform/libcore/+/master/luni/src/main/java/java/nio/DirectByteBuffer.java
-                    // DirectByteBuffer(long address, int capacity)
-                    directByteBufferConstructor = directByteBufferClass.getDeclaredConstructor(long.class, int.class);
-                    constructorType = DirectBufferConstructorType.ARGS_LONG_INT;
+                    // TODO We should use MethodHandle for Java7, which can avoid the cost of boxing with JIT optimization
+                    directByteBufferConstructor = directByteBufferClass.getDeclaredConstructor(long.class, int.class, Object.class);
+                    constructorType = DirectBufferConstructorType.ARGS_LONG_INT_REF;
                 }
-                catch (NoSuchMethodException e1) {
+                catch (NoSuchMethodException e0) {
                     try {
-                        directByteBufferConstructor = directByteBufferClass.getDeclaredConstructor(int.class, int.class);
-                        constructorType = DirectBufferConstructorType.ARGS_INT_INT;
+                        // https://android.googlesource.com/platform/libcore/+/master/luni/src/main/java/java/nio/DirectByteBuffer.java
+                        // DirectByteBuffer(long address, int capacity)
+                        directByteBufferConstructor = directByteBufferClass.getDeclaredConstructor(long.class, int.class);
+                        constructorType = DirectBufferConstructorType.ARGS_LONG_INT;
                     }
-                    catch (NoSuchMethodException e2) {
-                        Class<?> aClass = Class.forName("java.nio.MemoryBlock");
-                        mbWrap = aClass.getDeclaredMethod("wrapFromJni", int.class, long.class);
-                        mbWrap.setAccessible(true);
-                        directByteBufferConstructor = directByteBufferClass.getDeclaredConstructor(aClass, int.class, int.class);
-                        constructorType = DirectBufferConstructorType.ARGS_MB_INT_INT;
+                    catch (NoSuchMethodException e1) {
+                        try {
+                            directByteBufferConstructor = directByteBufferClass.getDeclaredConstructor(int.class, int.class);
+                            constructorType = DirectBufferConstructorType.ARGS_INT_INT;
+                        }
+                        catch (NoSuchMethodException e2) {
+                            Class<?> aClass = Class.forName("java.nio.MemoryBlock");
+                            mbWrap = aClass.getDeclaredMethod("wrapFromJni", int.class, long.class);
+                            mbWrap.setAccessible(true);
+                            directByteBufferConstructor = directByteBufferClass.getDeclaredConstructor(aClass, int.class, int.class);
+                            constructorType = DirectBufferConstructorType.ARGS_MB_INT_INT;
+                        }
                     }
                 }
             }
@@ -281,6 +289,8 @@ static ByteBuffer newByteBuffer(long address, int index, int length, ByteBuffer
         }
         try {
             switch (directBufferConstructorType) {
+                case ARGS_LONG_LONG:
+                    return (ByteBuffer) byteBufferConstructor.newInstance(address + index, (long) length);
                 case ARGS_LONG_INT_REF:
                     return (ByteBuffer) byteBufferConstructor.newInstance(address + index, length, reference);
                 case ARGS_LONG_INT: