Change keystore password from no password to a non blank password

I have a jks keystore with no password. When I run the command

keytool -list -keystore mykeystore.jks

And it prompts me for the keystore password, I simply hit 'enter'.

Please note that the keystore password IS NOT the default java password of 'changeit'. It is blank

When I try to run

keytool -storepasswd -keystore mykeystore.jks

to change the password to a non blank string. It firsts prompts me for the current password. Simply hitting enter since it is blank says

keytool -storepasswd -keystore mykeystore.jks
Enter keystore password:
Keystore password is too short - must be at least 6 characters 

Just to confirm with everyone that the password is not 'changeit'

keytool -storepasswd -keystore mykeystore.jks
Enter keystore password:  changeit
keytool error: java.io.IOException: Keystore was tampered with, or password was incorrect

Any idea how I can change the keystore password if the existing password is blank?

If you're trying to do stuff with the Java default system keystore (cacerts), then the default password is changeit.

You can list keys without needing the password (even if it prompts you) so don't take that as an indication that it is blank.

(Incidentally who in the history of Java ever has changed the default keystore password? They should have left it blank.)

Add -storepass to keytool arguments.

keytool -storepasswd -storepass '' -keystore mykeystore.jks

But also notice that -list command does not always require a password. I could execute follow command in both cases: without password or with valid password

$JAVA_HOME/bin/keytool -list -keystore $JAVA_HOME/jre/lib/security/cacerts