我在Ubuntu中安装了java，hadoop和flume。 当我运行水槽工作从twitter提取数据时，我得到如下错误; 不起诉这背后的问题。
sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
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TwitterException{exceptionCode=[d0031b0b-1db75522 db667dea-99334ae4 db667dea-99334ae4 db667dea-99334ae4], statusCode=-1, message=null, code=-1, retryAfter=-1, rateLimitStatus=null, version=3.0.3}
at twitter4j.internal.http.HttpClientImpl.request(HttpClientImpl.java:192)
at twitter4j.internal.http.HttpClientWrapper.request(HttpClientWrapper.java:61)
at twitter4j.internal.http.HttpClientWrapper.get(HttpClientWrapper.java:89)
at twitter4j.TwitterStreamImpl.getSampleStream(TwitterStreamImpl.java:176)
at twitter4j.TwitterStreamImpl$4.getStream(TwitterStreamImpl.java:164)
at twitter4j.TwitterStreamImpl$TwitterStreamConsumer.run(TwitterStreamImpl.java:462)
Caused by: javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
at sun.security.ssl.Alerts.getSSLException(Alerts.java:192)
at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1949)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:302)
at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:296)
at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1509)
at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:216)
at sun.security.ssl.Handshaker.processLoop(Handshaker.java:979)
at sun.security.ssl.Handshaker.process_record(Handshaker.java:914)
at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1062)
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1375)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1403)
at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1387)
at sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:559)
at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:185)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1513)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1441)
at java.net.HttpURLConnection.getResponseCode(HttpURLConnection.java:480)
at sun.net.www.protocol.https.HttpsURLConnectionImpl.getResponseCode(HttpsURLConnectionImpl.java:338)
at twitter4j.internal.http.HttpResponseImpl.<init>(HttpResponseImpl.java:34)
at twitter4j.internal.http.HttpClientImpl.request(HttpClientImpl.java:156)
... 5 more