try an alternative hack

libreoffice.spec

@@ -68,7 +68,7 @@ Source21:       http://dev-www.libreoffice.org/src/7c2549f6b0a8bb604e6c4c729ffdc
 %endif
 
 BuildRequires:  zip, findutils, autoconf, flex, bison, icu, gperf, gcc-c++
-BuildRequires:  binutils, java-devel < 1:1.7.0, jre >= 1.6.0, boost-devel
+BuildRequires:  binutils, java-devel < 1:1.7.0, java = 1:1.6.0, boost-devel
 BuildRequires:  python-devel, expat-devel, libxml2-devel, libxslt-devel, bc
 BuildRequires:  neon-devel, libcurl-devel, libidn-devel, pam-devel, cups-devel
 BuildRequires:  libXext-devel, libXt-devel, libICE-devel, libjpeg-devel, make