guava-libraries version 09-1 failed to build with openjdk-7

During a rebuild test on precise with default-jdk switched to openjdk-7, a build failure was detected for guava-libraries version 09-1.

See attached log for full build failure details.

This log snippet might also be of interest:

src/main/java/com/google/common/net/InternetDomainName.java:67: warning: unmappable character for encoding ASCII
 * internationalized domain names</a> such as {@code ??????.cn} are supported, as
                                                         ^
src/main/java/com/google/common/net/InternetDomainName.java:67: warning: unmappable character for encoding ASCII
 * internationalized domain names</a> such as {@code ??????.cn} are supported, as
                                                          ^
src/main/java/com/google/common/primitives/UnsignedBytes.java:24: warning: Unsafe is internal proprietary API and may be removed in a future release
import sun.misc.Unsafe;
               ^
src/main/java/com/google/common/primitives/UnsignedBytes.java:235: warning: Unsafe is internal proprietary API and may be removed in a future release
      static final Unsafe theUnsafe;
                   ^
src/main/java/com/google/common/primitives/UnsignedBytes.java:241: warning: Unsafe is internal proprietary API and may be removed in a future release
        theUnsafe = (Unsafe) AccessController.doPrivileged(
                     ^
src/main/java/com/google/common/primitives/UnsignedBytes.java:246: warning: Unsafe is internal proprietary API and may be removed in a future release
                  Field f = Unsafe.class.getDeclaredField("theUnsafe");
                            ^
11 warnings
find src -name *.java -and -type f -print0 | xargs -0 /usr/lib/jvm/default-java/bin/javadoc -classpath /usr/share/java/jsr305.jar:debian/_jh_build.guava -d debian/_jh_build.javadoc/api -quiet
Creating destination directory: "debian/_jh_build.javadoc/api/"
src/main/java/com/google/common/net/InternetDomainName.java:67: error: unmappable character for encoding ASCII
 * internationalized domain names</a> such as {@code ??????.cn} are supported, as
                                                     ^
src/main/java/com/google/common/net/InternetDomainName.java:67: error: unmappable character for encoding ASCII
 * internationalized domain names</a> such as {@code ??????.cn} are supported, as
                                                      ^
src/main/java/com/google/common/net/InternetDomainName.java:67: error: unmappable character for encoding ASCII
 * internationalized domain names</a> such as {@code ??????.cn} are supported, as
                                                       ^
src/main/java/com/google/common/net/InternetDomainName.java:67: error: unmappable character for encoding ASCII
 * internationalized domain names</a> such as {@code ??????.cn} are supported, as
                                                        ^
src/main/java/com/google/common/net/InternetDomainName.java:67: error: unmappable character for encoding ASCII
 * internationalized domain names</a> such as {@code ??????.cn} are supported, as
                                                         ^
src/main/java/com/google/common/net/InternetDomainName.java:67: error: unmappable character for encoding ASCII
 * internationalized domain names</a> such as {@code ??????.cn} are supported, as
                                                          ^
6 errors
make[1]: *** [override_dh_auto_build] Error 123
make[1]: Leaving directory `/«PKGBUILDDIR»'
make: *** [build] Error 2
dpkg-buildpackage: error: debian/rules build gave error exit status 2
────────────────────────────────────────────────────────────────────────────────
Build finished at 20111110-1438

Finished
────────

E: Build failure (dpkg-buildpackage died)