Unable to find valid certification path to requested target - error even after cert imported

Question

I have a Java client trying to access a server with a self-signed certificate.

When I try to Post to the server, I get the following error:

un

Answer 1

(repost from my other response)
Use cli utility keytool from java software distribution for import (and trust!) needed certificates

Sample:

1. From cli change dir to jre\bin

2. Check keystore (file found in jre\bin directory)
   keytool -list -keystore ..\lib\security\cacerts
   Password is changeit

3. Download and save all certificates in chain from needed server.

4. Add certificates (before need to remove "read-only" attribute on file "..\lib\security\cacerts"), run: keytool -alias REPLACE_TO_ANY_UNIQ_NAME -import -keystore ..\lib\security\cacerts -file "r:\root.crt"

accidentally I found such a simple tip. Other solutions require the use of InstallCert.Java and JDK

source: http://www.java-samples.com/showtutorial.php?tutorialid=210