code: private Class lookupVirtualMachineClass() {
          try {
              return ToolsClassFinder.lookupClass("com.sun.tools.attach.VirtualMachine");
          } catch (ClassNotFoundException exp) {
              throw new ProcessingException(
                      "Cannot find classes from tools.jar. The heuristics for loading tools.jar which contains\n" +
                      "essential classes for attaching to a running JVM could locate the necessary jar file.\n" +
                      "\n" +
                      "Please call this launcher with a qualified classpath on the command line like\n" +
                      "\n" +
                      "   java -cp path/to/tools.jar:" + options.getJarFileName() + " org.jolokia.jvmagent.client.AgentLauncher [options] <command> <ppid>\n",
                      exp,
                      options);
          }
      }
docs: lookup virtual machine class