Sometimes, you may require to change
default key store password in WSO2 prodcuts due to security reasons. 
Here are the steps when changing
keystore passwords:
Step 1: 
Navigate to wso2 server location:
ex: cd
$wso2_server/repository/resources/security
Step 2:
Change keystore password:
keytool -storepasswd -new [new password] -keystore [keystore name]
ex: keytool
-storepasswd -new simplenewpassword
-keystore wso2carbon.jks
Step 3:
Change Private Key password
keytool -keypasswd -alias wso2carbon -keystore wso2carbon.jks  
 Enter keystore password: <simplenewpassword>  
 Enter key password for <wso2carbon> wso2carbon  
 New key password for <wso2carbon>: <simplenewpassword>  
 Re-enter new key password for <wso2carbon>: <simplenewpassword>  
Both
keystore and private key password must be the same in some cases like
WSO2 BAM. Specially, in Thrift, we need to configure to use one
password for both.
Step 4:
Configure wso2 server (example taken here as WSO2 BAM)
- Change carbon.xml at @wso2_server/repository/conf
 
<KeyStore>  
      <!-- Keystore file location-->  
      <Location>${carbon.home}/repository/resources/security/wso2carbon.jks</Location>  
      <!-- Keystore type (JKS/PKCS12 etc.)-->  
      <Type>JKS</Type>  
      <!-- Keystore password-->  
      <Password>simplenewpassword</Password>  
      <!-- Private Key alias-->  
      <KeyAlias>wso2carbon</KeyAlias>  
      <!-- Private Key password-->  
      <KeyPassword>simplenewpassword</KeyPassword>  
 </KeyStore>  
 <RegistryKeyStore>  
      <!-- Keystore file location-->  
      <Location>${carbon.home}/repository/resources/security/wso2carbon.jks</Location>  
      <!-- Keystore type (JKS/PKCS12 etc.)-->  
      <Type>JKS</Type>  
      <!-- Keystore password-->  
      <Password>simplenewpassword</Password>  
      <!-- Private Key alias-->  
      <KeyAlias>wso2carbon</KeyAlias>  
      <!-- Private Key password-->  
      <KeyPassword>simplenewpassword</KeyPassword>  
 </RegistryKeyStore>  
- Change identtity.xml at @wso2_server/repository/conf
 
 <ThirftBasedEntitlementConfig>  
      <EnableThriftService>true</EnableThriftService>  
      <ReceivePort>${Ports.ThriftEntitlementReceivePort}</ReceivePort>          <ClientTimeout>10000</ClientTimeout>  
      <KeyStore>  
           <Location>${carbon.home}/repository/resources/security/wso2carbon.jks</Location>               <Password>simplenewpassword</Password>  
      </KeyStore>  
 </ThirftBasedEntitlementConfig>