On Tue, Aug 19, 2014 at 6:06 AM, Asma rabe <asma.rabe at gmail.com> wrote: > > I have java 1.7 installed on CentOS machine. when i tried to run java > program i got an error and found that i should run it using java 1.6. > > > Is the best solution to install Java 1.6 and have both java 1.6 and java > 1.7 at same time? or is there a better solution. Java is packaged with different names for the 1.6 and 1.7 openjdk versions. You can find all the relevant packages with 'yum search java' or 'yum search openjdk'. The corresponding -devel packages have the compilers in case you need more than the runtime. If all of your java applications will run on 1.6 you can simply remove any 1.7 packages you have and make sure 1.6 is installed. > If i should install both java 1.6 and 1.7 , how to do that ? You can install both with yum like any other packages. However, they both install in odd places and use a set of double symlinks managed by the alternatives package to put one or the other in your PATH as the default version. Obviously you can only have one default, but you may in fact need to run different applications that require different versions simultaneously - or different users on the same system may have different requirements. If you need to run a non-default version, you should export JAVA_HOME=/path/to/that/installation (which will be something obvious under ./usr/lib/jvm, but be sure you understand the symlinks) and execute the full path to java in the bin subdirectory of that location. And thank RedHat for making it so simple... -- Les Mikesell lesmikesell at gmail.com