fixes javadocs

Signed-off-by: Oleh Dokuka <shadowgun@i.ua>

build.gradle

@@ -109,8 +109,13 @@ subprojects {
         }
 
         javadoc {
+            def jdk = JavaVersion.current().majorVersion
+            def jdkJavadoc = "https://docs.oracle.com/javase/$jdk/docs/api/"
+            if (JavaVersion.current().isJava11Compatible()) {
+                jdkJavadoc = "https://docs.oracle.com/en/java/javase/$jdk/docs/api/"
+            }
             options.with {
-                links 'https://docs.oracle.com/javase/8/docs/api/'
+                links jdkJavadoc
                 links 'https://projectreactor.io/docs/core/release/api/'
                 links 'https://netty.io/4.1/api/'
             }

rsocket-core/src/main/java/io/rsocket/util/CharByteBufUtil.java

@@ -99,7 +99,7 @@ private static char[] checkCharSequenceBounds(char[] seq, int start, int end) {
   }
 
   /**
-   * Encode a {@link char[]} in <a href="http://en.wikipedia.org/wiki/UTF-8">UTF-8</a> and write it
+   * Encode a {@code char[]} in <a href="http://en.wikipedia.org/wiki/UTF-8">UTF-8</a> and write it
    * into {@link ByteBuf}.
    *
    * <p>This method returns the actual number of bytes written.
@@ -109,8 +109,8 @@ public static int writeUtf8(ByteBuf buf, char[] seq) {
   }
 
   /**
-   * Equivalent to <code>{@link #writeUtf8(ByteBuf, char[])
-   * writeUtf8(buf, seq.subSequence(start, end), reserveBytes)}</code> but avoids subsequence object
+   * Equivalent to {@link #writeUtf8(ByteBuf, char[])
+   * writeUtf8(buf, seq.subSequence(start, end), reserveBytes)} but avoids subsequence object
    * allocation if possible.
    *
    * @return actual number of bytes written