Remove jdk9-compile profile from pom.xml

dubbo-common/src/test/java/org/apache/dubbo/common/timer/HashedWheelTimerTest.java

@@ -17,15 +17,27 @@
 package org.apache.dubbo.common.timer;
 
 import org.apache.dubbo.common.utils.NamedThreadFactory;
+import org.apache.dubbo.common.utils.SystemPropertyConfigUtils;
 
 import java.lang.ref.WeakReference;
+import java.lang.reflect.AccessibleObject;
+import java.lang.reflect.Array;
+import java.lang.reflect.Field;
+import java.lang.reflect.GenericArrayType;
+import java.lang.reflect.ParameterizedType;
+import java.lang.reflect.Type;
+import java.lang.reflect.TypeVariable;
+import java.security.AccessController;
+import java.security.PrivilegedAction;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
 
 import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
+import sun.misc.Unsafe;
 
 import static org.awaitility.Awaitility.await;
 
@@ -171,4 +183,181 @@ void stopTaskTest() throws InterruptedException {
         // this will throw an exception
         Assertions.assertThrows(RuntimeException.class, () -> timer.newTimeout(new EmptyTask(), 5, TimeUnit.SECONDS));
     }
+
+    @Test
+    @DisplayName("Check whether sun.misc.Unsafe (used by latest Netty HashedWheelTimer) could be compiled or not.")
+    void unsafeTest() {
+        // attempt to access field Unsafe#theUnsafe
+        final Object maybeUnsafe = AccessController.doPrivileged(new PrivilegedAction<Object>() {
+            @Override
+            public Object run() {
+                try {
+                    final Field unsafeField = Unsafe.class.getDeclaredField("theUnsafe");
+                    // We always want to try using Unsafe as the access still works on java9 as well and
+                    // we need it for out native-transports and many optimizations.
+                    Throwable cause = ReflectionUtil.trySetAccessible(unsafeField, false);
+                    if (cause != null) {
+                        return cause;
+                    }
+                    // the unsafe instance
+                    return unsafeField.get(null);
+                } catch (NoSuchFieldException | IllegalAccessException | SecurityException e) {
+                    return e;
+                } catch (NoClassDefFoundError e) {
+                    // Also catch NoClassDefFoundError in case someone uses for example OSGI and it made
+                    // Unsafe unloadable.
+                    return e;
+                }
+            }
+        });
+
+        Assertions.assertInstanceOf(Unsafe.class, maybeUnsafe);
+    }
+
+    private static final class ReflectionUtil {
+
+        private ReflectionUtil() {}
+
+        /**
+         * Try to call {@link AccessibleObject#setAccessible(boolean)} but will catch any {@link SecurityException} and
+         * {@link java.lang.reflect.InaccessibleObjectException} and return it.
+         * The caller must check if it returns {@code null} and if not handle the returned exception.
+         */
+        public static Throwable trySetAccessible(AccessibleObject object, boolean checkAccessible) {
+            if (checkAccessible && !explicitTryReflectionSetAccessible0()) {
+                return new UnsupportedOperationException("Reflective setAccessible(true) disabled");
+            }
+            try {
+                object.setAccessible(true);
+                return null;
+            } catch (SecurityException e) {
+                return e;
+            } catch (RuntimeException e) {
+                return handleInaccessibleObjectException(e);
+            }
+        }
+
+        private static RuntimeException handleInaccessibleObjectException(RuntimeException e) {
+            // JDK 9 can throw an inaccessible object exception here; since Netty compiles
+            // against JDK 7 and this exception was only added in JDK 9, we have to weakly
+            // check the type
+            if ("java.lang.reflect.InaccessibleObjectException"
+                    .equals(e.getClass().getName())) {
+                return e;
+            }
+            throw e;
+        }
+
+        private static Class<?> fail(Class<?> type, String typeParamName) {
+            throw new IllegalStateException(
+                    "cannot determine the type of the type parameter '" + typeParamName + "': " + type);
+        }
+
+        /**
+         * Resolve a type parameter of a class that is a subclass of the given parametrized superclass.
+         *
+         * @param object                 The object to resolve the type parameter for
+         * @param parametrizedSuperclass The parametrized superclass
+         * @param typeParamName          The name of the type parameter to resolve
+         * @return The resolved type parameter
+         * @throws IllegalStateException if the type parameter could not be resolved
+         */
+        public static Class<?> resolveTypeParameter(
+                final Object object, Class<?> parametrizedSuperclass, String typeParamName) {
+            final Class<?> thisClass = object.getClass();
+            Class<?> currentClass = thisClass;
+            for (; ; ) {
+                if (currentClass.getSuperclass() == parametrizedSuperclass) {
+                    int typeParamIndex = -1;
+                    TypeVariable<?>[] typeParams = currentClass.getSuperclass().getTypeParameters();
+                    for (int i = 0; i < typeParams.length; i++) {
+                        if (typeParamName.equals(typeParams[i].getName())) {
+                            typeParamIndex = i;
+                            break;
+                        }
+                    }
+
+                    if (typeParamIndex < 0) {
+                        throw new IllegalStateException(
+                                "unknown type parameter '" + typeParamName + "': " + parametrizedSuperclass);
+                    }
+
+                    Type genericSuperType = currentClass.getGenericSuperclass();
+                    if (!(genericSuperType instanceof ParameterizedType)) {
+                        return Object.class;
+                    }
+
+                    Type[] actualTypeParams = ((ParameterizedType) genericSuperType).getActualTypeArguments();
+
+                    Type actualTypeParam = actualTypeParams[typeParamIndex];
+                    if (actualTypeParam instanceof ParameterizedType) {
+                        actualTypeParam = ((ParameterizedType) actualTypeParam).getRawType();
+                    }
+                    if (actualTypeParam instanceof Class) {
+                        return (Class<?>) actualTypeParam;
+                    }
+                    if (actualTypeParam instanceof GenericArrayType) {
+                        Type componentType = ((GenericArrayType) actualTypeParam).getGenericComponentType();
+                        if (componentType instanceof ParameterizedType) {
+                            componentType = ((ParameterizedType) componentType).getRawType();
+                        }
+                        if (componentType instanceof Class) {
+                            return Array.newInstance((Class<?>) componentType, 0)
+                                    .getClass();
+                        }
+                    }
+                    if (actualTypeParam instanceof TypeVariable) {
+                        // Resolved type parameter points to another type parameter.
+                        TypeVariable<?> v = (TypeVariable<?>) actualTypeParam;
+                        if (!(v.getGenericDeclaration() instanceof Class)) {
+                            return Object.class;
+                        }
+
+                        currentClass = thisClass;
+                        parametrizedSuperclass = (Class<?>) v.getGenericDeclaration();
+                        typeParamName = v.getName();
+                        if (parametrizedSuperclass.isAssignableFrom(thisClass)) {
+                            continue;
+                        }
+                        return Object.class;
+                    }
+
+                    return fail(thisClass, typeParamName);
+                }
+                currentClass = currentClass.getSuperclass();
+                if (currentClass == null) {
+                    return fail(thisClass, typeParamName);
+                }
+            }
+        }
+
+        private static boolean explicitTryReflectionSetAccessible0() {
+            // we disable reflective access
+            return Boolean.parseBoolean(SystemPropertyConfigUtils.getSystemProperty(
+                    "io.netty.tryReflectionSetAccessible",
+                    String.valueOf(javaVersion() < 9 || RUNNING_IN_NATIVE_IMAGE)));
+        }
+
+        private static final boolean RUNNING_IN_NATIVE_IMAGE =
+                SystemPropertyConfigUtils.getSystemProperty("org.graalvm.nativeimage.imagecode") != null;
+
+        private static int javaVersion() {
+            return majorVersion(SystemPropertyConfigUtils.getSystemProperty("java.specification.version", "1.6"));
+        }
+
+        private static int majorVersion(final String javaSpecVersion) {
+            final String[] components = javaSpecVersion.split("\\.");
+            final int[] version = new int[components.length];
+            for (int i = 0; i < components.length; i++) {
+                version[i] = Integer.parseInt(components[i]);
+            }
+
+            if (version[0] == 1) {
+                assert version[1] >= 6;
+                return version[1];
+            } else {
+                return version[0];
+            }
+        }
+    }
 }

dubbo-remoting/dubbo-remoting-api/src/test/java/org/apache/dubbo/remoting/buffer/ChannelBuffersTest.java

@@ -16,6 +16,7 @@
  */
 package org.apache.dubbo.remoting.buffer;
 
+import java.nio.Buffer;
 import java.nio.ByteBuffer;
 
 import org.junit.jupiter.api.Assertions;
@@ -75,7 +76,8 @@ void testWrappedBuffer() {
         channelBuffer = ChannelBuffers.wrappedBuffer(byteBuffer);
         Assertions.assertTrue(channelBuffer instanceof ByteBufferBackedChannelBuffer);
 
-        byteBuffer.position(byteBuffer.limit());
+        // be compatible with jdk8 by casting byteBuffer's type to its parent class - `java.nio.Buffer`.
+        ((Buffer) byteBuffer).position(byteBuffer.limit());
         channelBuffer = ChannelBuffers.wrappedBuffer(byteBuffer);
         Assertions.assertEquals(channelBuffer, EMPTY_BUFFER);
     }

dubbo-rpc/dubbo-rpc-triple/src/main/java/org/apache/dubbo/rpc/protocol/tri/TripleCustomerProtocolWrapper.java

@@ -19,6 +19,7 @@
 import org.apache.dubbo.common.utils.Assert;
 import org.apache.dubbo.common.utils.CollectionUtils;
 
+import java.nio.Buffer;
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
@@ -67,7 +68,8 @@ public static int readRawVarint32(ByteBuffer byteBuffer) {
             val = val << 7;
             val = val | (byteBuffer.get(index) & 0x7F);
         }
-        byteBuffer.position(currentPosition + varIntLength);
+        // be compatible with jdk8 by casting byteBuffer's type to its parent class - `java.nio.Buffer`.
+        ((Buffer) byteBuffer).position(currentPosition + varIntLength);
         return val;
     }
 

pom.xml

@@ -811,23 +811,6 @@
       </build>
     </profile>
 
-    <profile>
-      <id>jdk9-compile</id>
-      <activation>
-        <jdk>[1.9,)</jdk>
-      </activation>
-      <build>
-        <plugins>
-          <plugin>
-            <artifactId>maven-compiler-plugin</artifactId>
-            <configuration>
-              <release>8</release>
-            </configuration>
-          </plugin>
-        </plugins>
-      </build>
-    </profile>
-
     <profile>
       <id>jdk9-jdk11-spotless</id>
       <activation>