// For complete examples and data files, please go to https://github.com/groupdocs-signature/GroupDocs.Signature-for-Java
// setup Signature configuration
SignatureConfig signConfig = CommonUtilities.getConfiguration();
// instantiating the conversion handler
SignatureHandler handler = new SignatureHandler(signConfig);
VerifyOptionsCollection verifyOptionsCollection = new VerifyOptionsCollection();
// setup digital verification options
WordsVerifyDigitalOptions verifyOptions = new WordsVerifyDigitalOptions(CommonUtilities.getCertificatePath("certificate.cer"));
verifyOptions.setComments("Test1");
verifyOptions.setSignDateTimeFrom(new Date(2017, 1, 26, 14, 55, 57));
verifyOptions.setSignDateTimeTo(new Date(2017, 1, 26, 14, 55, 59));
//verify document
VerificationResult result = handler.verify(CommonUtilities.getStoragePath(fileName), verifyOptions);
System.out.println("Signed file verification result: " + result.isValid());