如何进入无密码保护的 Java 密钥库或更改密码？

我正在尝试将受信任的证书导入Java cacerts 密钥库 http://confluence.atlassian.com/display/JIRA/Connecting+to+SSL+services，但我有一个问题。我尝试列出现有的受信任证书，但密钥库似乎不受密码保护。

$ 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

我还尝试将密码从“无”更改为：

$ 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

这意味着 cacerts 密钥库不受密码保护

这是一个错误的假设。如果您仔细阅读，您会发现提供的列表没有验证密钥库的完整性，因为您没有提供密码。该列表不需要密码，但您的密钥库肯定有密码，如下所示：

为了验证其完整性，您必须提供密钥库密码。

Java 的默认 cacerts 密码是“changeit”，除非您使用的是 Mac，在某种程度上它是“changeme”。显然，从 Mountain Lion 开始（基于此处的评论和另一个答案），Mac 的密码现在也是“changeit”，可能是因为 Oracle 现在也在处理 Mac JVM 的分发。