Java Release : 6u4p
Java Builds : b01
VM flavors : server
VM Modes : -Xmixed
Java flags : -XX:+AggressiveOpts
Platform(s) : solaris-sparc, solaris-sparcv9
Hostnames with OS info : vm-t2000-01, nanonano (Solaris 10)

So, the failure is reproduced only on solaris-sparc/v9, with
-server -Xmixed -XX:+AggressiveOpts or
-d64 -server -Xmixed -XX:+AggressiveOpts

The failure is not reproduced with
- -Xint, -Xcomp
- without -XX:+AggressiveOpts
- on linux, sol-x86/amd, windows
- latest jdk7 (b23)
- latest jdk6u4 (b09)
- with rt.jar from latest 6u4 (b09)

Running the tests with latest jdk6u4b09 but with jvm copied from 6u4p01 results in tests failure. So, the problem is 6u4p specific and is in HotSpot

Test cases:
 java/lang/Character/Supplementary.java
 java/lang/String/Supplementary.java
 java/lang/StringBuffer/Supplementary.java
 java/lang/StringBuilder/Supplementary.java

Error Log :
1. java/lang/String/Supplementary.java fails with
java.lang.RuntimeException: Error: offsetByCodePoints(input[0], 10, -14) returned an unexpected value. got 0x9, expecte
d 0xa
        at Supplementary.check(Supplementary.java:589)
        at Supplementary.test9(Supplementary.java:412)
        at Supplementary.main(Supplementary.java:19)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.sun.javatest.regtest.MainWrapper$MainThread.run(MainWrapper.java:78)
        at java.lang.Thread.run(Thread.java:619)

2. java/lang/Character/Supplementary.java fails with
   java.lang.RuntimeException: isValidCodePoint failed with 0xffef2a3e
        at Supplementary.test00(Supplementary.java:95)
        at Supplementary.main(Supplementary.java:25)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.sun.javatest.regtest.MainWrapper$MainThread.run(MainWrapper.java:78)
        at java.lang.Thread.run(Thread.java:619)

3. java/lang/StringBuffer/Supplementary.java fails with
java.lang.RuntimeException: Error: offsetByCodePoints(input[4], 5, -11) returned an unexpected value. got 0x4, expected
 0x5
        at Supplementary.check(Supplementary.java:357)
        at Supplementary.test6(Supplementary.java:252)
        at Supplementary.main(Supplementary.java:16)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.sun.javatest.regtest.MainWrapper$MainThread.run(MainWrapper.java:78)
        at java.lang.Thread.run(Thread.java:619)

4. java/lang/StringBuilder/Supplementary.java fails with
java.lang.RuntimeException: Error: offsetByCodePoints(input[4], 5, -11) returned an unexpected value. got 0x4, expected
 0x5
        at Supplementary.check(Supplementary.java:357)
        at Supplementary.test6(Supplementary.java:252)
        at Supplementary.main(Supplementary.java:16)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at com.sun.javatest.regtest.MainWrapper$MainThread.run(MainWrapper.java:78)
        at java.lang.Thread.run(Thread.java:619)