Android Question Keystore file error: unknown format type

[asales]

I tried to create a keystore file to sign my app and I received the message "Keystore was created successfully", but the field "Signature (read only)" showed this message:

Error: Tipo de armazenamento de chaves: JKS
Fornecedor de armazenamento de chaves: SUN
erro de keytool: java.lang.IllegalArgumentException: unknown format type at
java.lang.IllegalArgumentException: unknown format type at
    at java.text.MessageFormat.makeFormat(MessageFormat.java:1442)
    at java.text.MessageFormat.applyPattern(MessageFormat.java:458)
    at java.text.MessageFormat.<init>(MessageFormat.java:350)
    at sun.security.tools.KeyTool.doPrintEntries(KeyTool.java:1649)
    at sun.security.tools.KeyTool.doCommands(KeyTool.java:871)
    at sun.security.tools.KeyTool.run(KeyTool.java:172)
    at sun.security.tools.KeyTool.main(KeyTool.java:166)

What's happening?

How to fix it?

Thanks in advance to who can help me.

 

[Erel]

Does it happen with every key you create?

 

[asales]

Yes Erel, but I solved the problem with upgrade the JDK 6 to JDK 7. It´s ok, now. Thanks.