CertPathValidatorException is thrown if there are not certificates in OCSP responce:

java.security.cert.CertPathValidatorException: Responder's certificate is not trusted for signing OCSP responses
at sun.security.provider.certpath.PKIXMasterCertPathValidator.validate(PKIXMasterCertPathValidator.java:159)
at sun.security.provider.certpath.PKIXCertPathValidator.doValidate(PKIXCertPathValidator.java:351)
at sun.security.provider.certpath.PKIXCertPathValidator.engineValidate(PKIXCertPathValidator.java:191)
at java.security.cert.CertPathValidator.validate(CertPathValidator.java:279)
at TestOCSP.run(TestOCSP.java:211)
at TestOCSP.main(TestOCSP.java:52)