code: public T execute() {
          if (isWindows()) {
              return onWindows();
          } else if (isMac()) {
              return onMac();
          } else if (isUnix()) {
              return onUnix();
          } else if (isSolaris()) {
              return onSolaris();
          } else {
              throw new IllegalStateException("Invalid operating system " + os);
          }
      }
docs: Main method that should be executed. This will return the proper result depending on your platform.
  
  @return the result