See full tutorial at https://cedricleruth.com/how-to-configure-https-ssl-on-your-weblogic-application/

GenerateSelfSignedSSLCertificateWithKeytool.bash

# Open a command terminal in the bin folded of your java installation (e.g: C:\Program File(x86)\Java\jreXXXX\bin)
# In the commands below :
#   - selfsigned is the name of the certificate
#   - storPass is the password of the keystore and truststore
#   - keyPass is the password of the certificate
# You can change those values for yours

#Generate the keystore.jks
keytool -genkeypair -alias selfsigned -keyalg RSA -keysize 2048 -validity 365 -keypass keyPass -storepass storPass -keystore keystore.jks
#Enter your informations when prompt
#Be aware those information will be visible in your browser

#Export the selfsigned.cer from the keystore.jks
keytool -exportcert -alias selfsigned -file root.cer -keystore keystore.jks -storepass storPass

#Generate the truststore.jks
keytool -importcert -alias selfsigned -file root.cer -keystore truststore.jks -storepass storPass

#The jks files are available in the folder