Exception in thread "main" com.braintreegateway.exceptions.UnexpectedException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at com.braintreegateway.util.Http.httpRequest(Http.java:93)
	at com.braintreegateway.util.Http.post(Http.java:52)
	at com.braintreegateway.TransactionGateway.sale(TransactionGateway.java:104)
	at edu.ua.crimson.planr.braintree.BrainTree.main(BrainTree.java:38)
Caused by: javax.net.ssl.SSLHandshakeException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at java.base/sun.security.ssl.Alert.createSSLException(Alert.java:131)
	at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:320)
	at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:263)
	at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:258)
	at java.base/sun.security.ssl.CertificateMessage$T12CertificateConsumer.checkServerCerts(CertificateMessage.java:641)
	at java.base/sun.security.ssl.CertificateStatus$CertificateStatusConsumer.consume(CertificateStatus.java:295)
	at java.base/sun.security.ssl.SSLHandshake.consume(SSLHandshake.java:392)
	at java.base/sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:443)
	at java.base/sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:421)
	at java.base/sun.security.ssl.TransportContext.dispatch(TransportContext.java:177)
	at java.base/sun.security.ssl.SSLTransport.decode(SSLTransport.java:164)
	at java.base/sun.security.ssl.SSLSocketImpl.decode(SSLSocketImpl.java:1152)
	at java.base/sun.security.ssl.SSLSocketImpl.readHandshakeRecord(SSLSocketImpl.java:1063)
	at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:402)
	at java.base/sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:567)
	at java.base/sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:185)
	at java.base/sun.net.www.protocol.http.HttpURLConnection.getOutputStream0(HttpURLConnection.java:1362)
	at java.base/sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:1337)
	at java.base/sun.net.www.protocol.https.HttpsURLConnectionImpl.getOutputStream(HttpsURLConnectionImpl.java:246)
	at com.braintreegateway.util.Http.httpRequest(Http.java:76)
	... 3 more
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at java.base/sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:385)
	at java.base/sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:290)
	at java.base/sun.security.validator.Validator.validate(Validator.java:264)
	at java.base/sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:313)
	at java.base/sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:222)
	at java.base/sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:129)
	at java.base/sun.security.ssl.CertificateMessage$T12CertificateConsumer.checkServerCerts(CertificateMessage.java:625)
	... 18 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at java.base/sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141)
	at java.base/sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126)
	at java.base/java.security.cert.CertPathBuilder.build(CertPathBuilder.java:297)
	at java.base/sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:380)
	... 24 more