While trying to establish an HTTPS connection to a Web Service, we get the exception:
PKIX path building failed: unable to find valid certification path to requested target
In this case I was trying to establish HTTPS connection to MS Exchange 2007 Web service. What this usually means is that the server is using a test certificate.

WSO2 WSAS should recognize this test certificate by means of truststore. One way is to upload keystore in WSO2 WSAS Admin UI. But uploading in Admin UI requires a private key.

Below is the alternative way:
1 Generated truststore using
2 Place the generated trustsore file (jssecacerts) in "wso2wsas-2.1\conf".
3 In the program, set the System property
 System.setProperty("", "conf/jssecacerts");
 System.setProperty("", "<password>");

Best Regards,