CertificateException: No name matching ssl.someUrl.de found

Question

I\'m trying to connect to one of my servers through ssl, with Java. I tried a lot of options here is my best try:

I generate a jssecacerts with the recommendet scrip

Answer 1

In case, it helps someone:

Use case: i am using a self-signed certificate for my development on localhost.

Error: Caused by: java.security.cert.CertificateException: No name matching localhost found

Solution: When you generate your self-signed certicate, make sure you answer this question like that(See Bruno's answer for the why):

What is your first and last name?
  [Unknown]:  localhost

As a bonus, here are my steps:
1. Generate self-signed certificate:

keytool -genkeypair -alias netty -storetype PKCS12 -keyalg RSA -keysize 2048 -keystore keystore.p12 -validity 4000
Enter keystore password: ***
Re-enter new password: ***
What is your first and last name?
  [Unknown]:  localhost
...

2. Copy the certificate in src/main/resources(if necessary)

3. Update the cacerts
keytool -v -importkeystore -srckeystore keystore.p12 -srcstoretype pkcs12 -destkeystore "%JAVA_HOME%\jre\lib\security\cacerts" -deststoretype jks

4. Update your config(in my case application.properties):

server.port=8443
server.ssl.key-store=classpath:keystore.p12
server.ssl.key-store-password=jumping_monkey
server.ssl.key-store-type=pkcs12
server.ssl.key-alias=netty

Cheers