tools.jar contains the utilities to compile java source into class files.

While using ColdFusion Web services stubs have to be generated.

So, this utility is required for this feature to be functional.

The tools.jar is shipped by default with ColdFusion along with full installation of ColdFusion which would be same version of the jre that ColdFusion is shipped with.

If you are just using this default installation and the built-in jre, your ColdFusion web services do work fine.

However, due to security bugs or platform support you would want to update the jre version that ColdFusion runs on.

Once you do that, please make sure to copy the tools.jar file manually from {JDK_Home}/lib to {cf_install_home}/cfusion/lib/

Only JDK contains the tools.jar file not the jre installation. You don't have to install JDK on the machine where ColdFusion is installed. You can just have jre on this machine and get tools.jar from any other machine's JDK installation.

And also make sure that the earlier stubs are cleared from {cf_install_home}/cfusion/stubs/ to get the newly compiled classes.

It is necessary to update tools.jar ONLY if you are upgrading the jre to a a higher major version.

Say, if you are upgrading from 1.8 U5 to 1.8 U51 you don't have to update tools.jar file.

But, say   if you are upgrading from 1.7 U55 to 1.8 U51, you have to update tools.jar file.

 

Another case where you would want to update the tools.jar is JEE deployments.

Say, if you are using Websphere application server with IBM JDK, you have to place the corresponding JDK's tools.jar under  {cf_install_home}/cfusion/lib/.

The same applies to any other application server as well.

The simple rule is that tools.jar has to be from the same major version of Java (minor version doesn’t matter) that ColdFusion runs on.

 

This applies to any version of ColdFusion and the same applies to all platforms.

You can copy tools.jar from Windows machine to Solaris macine as well as long as the version is correct.