Just taking a look at CentOS rpms at two of its mirrors: http://ftp.hol.gr/LinuxSection/distributions/centos/4.4/os/i386/CentOS/RPMS/ http://helios.imbb.forth.gr/mirrors/centos/4.4/os/i386/CentOS/RPMS/ I saw two file version differences: java-1.4.2-gcj-compat-1.4.2.0-27jpp.noarch.rpm java-1.4.2-gcj-compat-devel-1.4.2.0-27jpp.noarch.rpm while SL 4.4 i386 has: java-1.4.2-gcj-compat-1.4.2.0-26jpp.noarch.rpm java-1.4.2-gcj-compat-devel-1.4.2.0-26jpp.noarch.rpm (-27 vs -26). I don't know if it is anything important.