Yes they did. They just used a Adenovirus to introduce the mRna package
Adenovirus type 26 expressing the SARS-CoV-2 spike protein
The Johnson & Johnson vaccine does not use mRNA, described above, to build an immune response against COVID-19. Instead, it uses a different virus, an adenovirus (the common cold), to show the body what COVID-19 looks like.
The adenovirus is modified so that it is not able to cause illness or create more viruses in the body. It is designed to deliver genetic information for the COVID-19 spike protein to human cells.
Similar to the mRNA vaccines, our own body’s cells then make the COVID-19 spike protein and begin to create antibodies specifically designed to fight COVID-19, if we ever encounter the real virus.