I have not verified your way of making PKI self-signed TLS/SSL server certificate and server private key files in the PEM format.
Anyway,
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Assuming you refer to self-signed public key server certificate in both cases, you generate the keypair in the PEM format on the java way. What conversion does java way need then?
What do you mean with forking? Fork what?
Using PowerShell instead of your self-made java way could be a coequal alternative for making self-signed public key server certificate and server private key PEM files, though PowerShell features in general strongly depend on the version of Windows possibly for commercial reason and your way probably does not.
Anyway, if no conversion was needed, the java way would be the one to go for people like @DameLyngdoh, who is using a university system with Java already installed, but not allowing installations, cf. initial post in this topic. However, beware of coming up against a brick wall when using self-signed public key server certificate.
After starting the Solid server, do you encounter the reference symptom?