code: public void addEnv(final Environment.Variable var) {
      if (this.env == null) {
        this.env = new Environment();
        this.newEnvironment = true;
        if (this.processor != null) {
          // Change the environment in the processor
          setProcessor(this.processor);
        }
      }
      this.env.addVariable(var);
    }
docs: Add an environment variable to the launched process.