如何进入无密码保护的 Java 密钥存储库或更改密码？

我正在尝试将一个受信任的证书导入到 Java 捕获密钥库中，但是我遇到了一个问题。我试图列出现有的受信任证书，但密钥存储库似乎没有密码保护。

$ keytool -list -keystore cacerts
Enter keystore password:


*****************  WARNING WARNING WARNING  *****************
* The integrity of the information stored in your keystore  *
* has NOT been verified!  In order to verify its integrity, *
* you must provide your keystore password.                  *
*****************  WARNING WARNING WARNING  *****************


Keystore type: JKS
Keystore provider: SUN


Your keystore contains 76 entries

我尝试导入一个受信任的证书:

$ keytool -importcert -alias "JiraCert" -file /root/c9ssl.crt -keystore /etc/java-6-sun/security/cacerts
Enter keystore password:
Keystore password is too short - must be at least 6 characters
Enter keystore password:
Keystore password is too short - must be at least 6 characters
Enter keystore password:
Keystore password is too short - must be at least 6 characters
Too many failures - try later

我还试着把密码从“无”改成了:

$ keytool -storepasswd -keystore cacerts.back
Enter keystore password:
Keystore password is too short - must be at least 6 characters
Enter keystore password:
Keystore password is too short - must be at least 6 characters
Enter keystore password:
Keystore password is too short - must be at least 6 characters
Too many failures - try later