EVALUATION

The submitter is correct and there is a regression since 6u10. The regression is caused by the changes for 6546113 that went into 6u10 to address problems caused by 4997655. Yes, we goofed big time here. These issues should have been caught during code review or by tests. Our plan for this issue is to fix it in jdk7 first and let it bake before doing into a jdk6 update.
                                     

SUGGESTED FIX

hg diff src/share/classes/java/nio test/java/nio/Buffer/Basic.java test/java/nio/Buffer/Basic-X.java
diff -r a8d9e8cb38bb src/share/classes/java/nio/ByteBufferAs-X-Buffer.java
--- a/src/share/classes/java/nio/ByteBufferAs-X-Buffer.java     Wed Mar 04 15:09:14 2009 +0800
+++ b/src/share/classes/java/nio/ByteBufferAs-X-Buffer.java     Mon Mar 09 13:18:24 2009 +0000
@@ -196,10 +196,12 @@ class ByteBufferAs$Type$Buffer$RW$$BO$

         if ((start < 0) || (end > len) || (start > end))
             throw new IndexOutOfBoundsException();
-        int sublen = end - start;
-        int off = offset + ((pos + start) << $LG_BYTES_PER_VALUE$);
-        assert (off >= 0);
-        return new ByteBufferAsCharBuffer$RW$$BO$(bb, -1, 0, sublen, sublen, off);
+        return new ByteBufferAsCharBuffer$RW$$BO$(bb,
+                                                  -1,
+                                                  pos + start,
+                                                  pos + end,
+                                                  capacity(),
+                                                  offset);
     }

 #end[char]
diff -r a8d9e8cb38bb src/share/classes/java/nio/Direct-X-Buffer.java
--- a/src/share/classes/java/nio/Direct-X-Buffer.java   Wed Mar 04 15:09:14 2009 +0800
+++ b/src/share/classes/java/nio/Direct-X-Buffer.java   Mon Mar 09 13:18:24 2009 +0000
@@ -412,10 +412,12 @@ class Direct$Type$Buffer$RW$$BO$

         if ((start < 0) || (end > len) || (start > end))
             throw new IndexOutOfBoundsException();
-        int sublen = end - start;
-        int off = (pos + start) << $LG_BYTES_PER_VALUE$;
-        assert (off >= 0);
-        return new DirectCharBuffer$RW$$BO$(this, -1, 0, sublen, sublen, off);
+        return new DirectCharBuffer$RW$$BO$(this,
+                                            -1,
+                                            pos + start,
+                                            pos + end,
+                                            capacity(),
+                                            offset);
     }

 #end[char]
diff -r a8d9e8cb38bb src/share/classes/java/nio/Heap-X-Buffer.java
--- a/src/share/classes/java/nio/Heap-X-Buffer.java     Wed Mar 04 15:09:14 2009 +0800
+++ b/src/share/classes/java/nio/Heap-X-Buffer.java     Mon Mar 09 13:18:24 2009 +0000
@@ -572,10 +572,13 @@ class Heap$Type$Buffer$RW$
             || (end > length())
             || (start > end))
             throw new IndexOutOfBoundsException();
-        int len = end - start;
+        int pos = position();
         return new HeapCharBuffer$RW$(hb,
-                                      -1, 0, len, len,
-                                      offset + position() + start);
+                                      -1,
+                                      pos + start,
+                                      pos + end,
+                                      capacity(),
+                                      offset);
     }

 #end[char]
diff -r a8d9e8cb38bb src/share/classes/java/nio/StringCharBuffer.java
--- a/src/share/classes/java/nio/StringCharBuffer.java  Wed Mar 04 15:09:14 2009 +0800
+++ b/src/share/classes/java/nio/StringCharBuffer.java  Mon Mar 09 13:18:24 2009 +0000
@@ -102,10 +102,12 @@ class StringCharBuffer
     public final CharBuffer subSequence(int start, int end) {
         try {
             int pos = position();
-            return new StringCharBuffer(str, -1,
+            return new StringCharBuffer(str,
+                                        -1,
                                         pos + checkIndex(start, pos),
                                         pos + checkIndex(end, pos),
-                                        remaining(), offset);
+                                        capacity(),
+                                        offset);
         } catch (IllegalArgumentException x) {
             throw new IndexOutOfBoundsException();
         }
diff -r a8d9e8cb38bb test/java/nio/Buffer/Basic-X.java
--- a/test/java/nio/Buffer/Basic-X.java Wed Mar 04 15:09:14 2009 +0800
+++ b/test/java/nio/Buffer/Basic-X.java Mon Mar 09 13:18:24 2009 +0000
@@ -366,7 +366,10 @@ public class Basic$Type$
         b.position(2);
         ck(b, b.charAt(1), 'd');
         CharBuffer c = (CharBuffer)b.subSequence(1, 4);
-        ck(b, b.subSequence(1, 4).toString().equals("def"));
+        ck(c, c.capacity(), b.capacity());
+        ck(c, c.position(), b.position()+1);
+        ck(c, c.limit(), b.position()+4);
+        ck(c, b.subSequence(1, 4).toString().equals("def"));

         // 4938424
         b.position(4);
@@ -722,6 +725,8 @@ public class Basic$Type$
         ck(b, start, b.position());
         ck(b, end, b.limit());
         ck(b, s.length(), b.capacity());
+        b.position(6);
+        ck(b, b.subSequence(0,3).toString().equals("ghi"));

         // The index, relative to the position, must be non-negative and
         // smaller than remaining().
diff -r a8d9e8cb38bb test/java/nio/Buffer/Basic.java
--- a/test/java/nio/Buffer/Basic.java   Wed Mar 04 15:09:14 2009 +0800
+++ b/test/java/nio/Buffer/Basic.java   Mon Mar 09 13:18:24 2009 +0000
@@ -25,7 +25,7 @@
  * @summary Unit test for buffers
  * @bug 4413135 4414911 4416536 4416562 4418782 4471053 4472779 4490253 4523725
  *      4526177 4463011 4660660 4661219 4663521 4782970 4804304 4938424 6231529
- *      6221101 6234263 6535542 6591971 6593946
+ *      6221101 6234263 6535542 6591971 6593946 6795561
  * @author Mark Reinhold
  */