Call position method of java.nio.Buffer instead of java.nio.ByteBuffer to be compatible with jdk8

Author: zrlw

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;
     }