i follow this issue
https://github.com/microsoft/malmo/issues/221
set gradle.properties in my $HOME/.gradle
And then, raise PKIX path building failed
INFO:minerl.env.malmo.instance.9177f3:Starting Minecraft process: ['/tmp/tmpes0p__ok/Minecraft/launchClient.sh', '-port', '9001', '-env', '-runDir', '/tmp/tmpes0p__ok/Minecraft/run']
INFO:minerl.env.malmo.instance.9177f3:Starting process watcher for process 87740 @ localhost:9001
DEBUG:minerl.env.malmo.instance.9177f3:Downloading https://services.gradle.org/distributions/gradle-2.14-bin.zip
DEBUG:minerl.env.malmo.instance.9177f3:
DEBUG:minerl.env.malmo.instance.9177f3:Exception in thread "main" 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
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.Alerts.getSSLException(Alerts.java:192)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1946)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:316)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:310)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1639)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:223)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1037)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.Handshaker.process_record(Handshaker.java:965)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1064)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1367)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1395)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1379)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:559)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:185)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.net.www.protocol.http.HttpURLConnection.followRedirect0(HttpURLConnection.java:2729)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.net.www.protocol.http.HttpURLConnection.followRedirect(HttpURLConnection.java:2641)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1824)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1492)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:263)
DEBUG:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.Download.downloadInternal(Download.java:58)
DEBUG:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.Download.download(Download.java:44)
DEBUG:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.Install$1.call(Install.java:59)
DEBUG:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.Install$1.call(Install.java:46)
DEBUG:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.ExclusiveFileAccessManager.access(ExclusiveFileAccessManager.java:65)
DEBUG:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.Install.createDist(Install.java:46)
DEBUG:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:126)
DEBUG:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:61)
DEBUG:minerl.env.malmo.instance.9177f3:Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:397)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:302)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.validator.Validator.validate(Validator.java:262)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:229)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:124)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1621)
DEBUG:minerl.env.malmo.instance.9177f3: ... 22 more
DEBUG:minerl.env.malmo.instance.9177f3:Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126)
DEBUG:minerl.env.malmo.instance.9177f3: at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280)
DEBUG:minerl.env.malmo.instance.9177f3: at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:392)
DEBUG:minerl.env.malmo.instance.9177f3: ... 28 more
ERROR:minerl.env.malmo.instance.9177f3:Downloading https://services.gradle.org/distributions/gradle-2.14-bin.zip
ERROR:minerl.env.malmo.instance.9177f3:
ERROR:minerl.env.malmo.instance.9177f3:Exception in thread "main" 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
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.Alerts.getSSLException(Alerts.java:192)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.SSLSocketImpl.fatal(SSLSocketImpl.java:1946)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:316)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.Handshaker.fatalSE(Handshaker.java:310)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1639)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:223)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.Handshaker.processLoop(Handshaker.java:1037)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.Handshaker.process_record(Handshaker.java:965)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1064)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1367)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1395)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1379)
ERROR:minerl.env.malmo.instance.9177f3: at sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:559)
ERROR:minerl.env.malmo.instance.9177f3: at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:185)
ERROR:minerl.env.malmo.instance.9177f3: at sun.net.www.protocol.http.HttpURLConnection.followRedirect0(HttpURLConnection.java:2729)
ERROR:minerl.env.malmo.instance.9177f3: at sun.net.www.protocol.http.HttpURLConnection.followRedirect(HttpURLConnection.java:2641)
ERROR:minerl.env.malmo.instance.9177f3: at sun.net.www.protocol.http.HttpURLConnection.getInputStream0(HttpURLConnection.java:1824)
ERROR:minerl.env.malmo.instance.9177f3: at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1492)
ERROR:minerl.env.malmo.instance.9177f3: at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:263)
ERROR:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.Download.downloadInternal(Download.java:58)
ERROR:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.Download.download(Download.java:44)
ERROR:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.Install$1.call(Install.java:59)
ERROR:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.Install$1.call(Install.java:46)
ERROR:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.ExclusiveFileAccessManager.access(ExclusiveFileAccessManager.java:65)
ERROR:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.Install.createDist(Install.java:46)
ERROR:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.WrapperExecutor.execute(WrapperExecutor.java:126)
ERROR:minerl.env.malmo.instance.9177f3: at org.gradle.wrapper.GradleWrapperMain.main(GradleWrapperMain.java:61)
ERROR:minerl.env.malmo.instance.9177f3:Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:397)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:302)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.validator.Validator.validate(Validator.java:262)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:229)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:124)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1621)
ERROR:minerl.env.malmo.instance.9177f3: ... 22 more
ERROR:minerl.env.malmo.instance.9177f3:Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126)
ERROR:minerl.env.malmo.instance.9177f3: at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280)
ERROR:minerl.env.malmo.instance.9177f3: at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:392)
ERROR:minerl.env.malmo.instance.9177f3: ... 28 more