I have to access a webservice hosted at port 443.Service provider has shared three certificate with us.
The issue here is the alias you used while importing the certificate which is similar to the one you used while creating the JKS store. Just change the alias and it will solve your issue. The source document [1] needs to be corrected accordingly.
[1] http://docs.oracle.com/cd/E19509-01/820-3503/ggfgo/index.html