===== Java + StartSSL unable to find valid certification path to requested target =====

**Problema**. La máquina virtual de Java no tiene los certificados raiz de StartSSL. Cualquier petición https a dominios con una firma de certificado de dicha CA devuelven un error como el siguiente.
<code>ExceptionConverter: 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:1937)
	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:1478)
	at sun.security.ssl.ClientHandshaker.processMessage(ClientHandshaker.java:212)
	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:1050)
	at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1363)
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1391)
	at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1375)
	at sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:563)
	at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:185)
	at sun.net.www.protocol.http.HttpURLConnection.getOutputStream0(HttpURLConnection.java:1282)
	at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:1257)
	at sun.net.www.protocol.https.HttpsURLConnectionImpl.getOutputStream(HttpsURLConnectionImpl.java:250)
	at com.lowagie.text.pdf.TSAClientBouncyCastle.getTSAResponse(Unknown Source)
	at com.lowagie.text.pdf.TSAClientBouncyCastle.getTimeStampToken(Unknown Source)
	at com.lowagie.text.pdf.TSAClientBouncyCastle.getTimeStampToken(Unknown Source)
	at com.lowagie.text.pdf.PdfPKCS7.getEncodedPKCS7(Unknown Source)
	at net.sf.jsignpdf.SignerLogic.signFile(SignerLogic.java:387)
	at net.sf.jsignpdf.Signer.signFiles(Signer.java:242)
	at net.sf.jsignpdf.Signer.main(Signer.java:137)
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 sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:387)
	at sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:292)
	at sun.security.validator.Validator.validate(Validator.java:260)
	at sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:324)
	at sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:229)
	at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:105)
	at net.sf.jsignpdf.ssl.DynamicX509TrustManager.checkServerTrusted(DynamicX509TrustManager.java:111)
	at sun.security.ssl.AbstractTrustManagerWrapper.checkServerTrusted(SSLContextImpl.java:922)
	at sun.security.ssl.ClientHandshaker.serverCertificate(ClientHandshaker.java:1460)
	... 19 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:145)
	at sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:131)
	at java.security.cert.CertPathBuilder.build(CertPathBuilder.java:280)
	at sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:382)
	... 27 more
INFO  Finished: Creating of signature failed.</code>

**Solución**: Importar a la JVM (cacerts / jssecacerts) los certificados StartSSL CA en Java.
<code bash StartSSL_java.sh>
#!/bin/sh
#
# Downloads and installs the startssl CA certs into the global java keystore
# Author: Klaus Reimer <k@ailis.de>
#

# Check if JAVA_HOME is set
if [ "$JAVA_HOME" = "" ]
then
    echo "ERROR: JAVA_HOME must be set."
    exit 1
fi

# Check if cacerts file is present
if [ ! -f $JAVA_HOME/jre/lib/security/cacerts ]
then
    echo "ERROR: \$JAVA_HOME/jre/lib/security/cacerts not found. JAVA_HOME set correctly?"
    exit 1
fi

# Download the startssl certs
echo "Downloading certs..."
wget --quiet --continue http://www.startssl.com/certs/ca.crt
wget --quiet --continue http://www.startssl.com/certs/sub.class1.server.ca.crt
wget --quiet --continue http://www.startssl.com/certs/sub.class2.server.ca.crt
wget --quiet --continue http://www.startssl.com/certs/sub.class3.server.ca.crt
wget --quiet --continue http://www.startssl.com/certs/sub.class4.server.ca.crt

# Install certs into global keystore
echo "Adding certs to cacerts keystore (sudo password required)..."
keytool -import -trustcacerts -keystore $JAVA_HOME/jre/lib/security/cacerts -storepass changeit -noprompt -alias startcom.ca -file ca.crt
keytool -import -trustcacerts -keystore $JAVA_HOME/jre/lib/security/cacerts -storepass changeit -noprompt -alias startcom.ca.sub.class1 -file sub.class1.server.ca.crt
keytool -import -trustcacerts -keystore $JAVA_HOME/jre/lib/security/cacerts -storepass changeit -noprompt -alias startcom.ca.sub.class2 -file sub.class2.server.ca.crt
keytool -import -trustcacerts -keystore $JAVA_HOME/jre/lib/security/cacerts -storepass changeit -noprompt -alias startcom.ca.sub.class3 -file sub.class3.server.ca.crt
keytool -import -trustcacerts -keystore $JAVA_HOME/jre/lib/security/cacerts -storepass changeit -noprompt -alias startcom.ca.sub.class4 -file sub.class4.server.ca.crt

# If jsse is installed then also put the certs into jssecacerts keystore
if [ -f $JAVA_HOME/jre/lib/security/jssecacerts ]
then
    echo "Adding certs to jssecacerts keystore (sudo password required)..."
     keytool -import -trustcacerts -keystore $JAVA_HOME/jre/lib/security/jssecacerts -storepass changeit -noprompt -alias startcom.ca -file ca.crt
     keytool -import -trustcacerts -keystore $JAVA_HOME/jre/lib/security/jssecacerts -storepass changeit -noprompt -alias startcom.ca.sub.class1 -file sub.class1.server.ca.crt
     keytool -import -trustcacerts -keystore $JAVA_HOME/jre/lib/security/jssecacerts -storepass changeit -noprompt -alias startcom.ca.sub.class2 -file sub.class2.server.ca.crt
     keytool -import -trustcacerts -keystore $JAVA_HOME/jre/lib/security/jssecacerts -storepass changeit -noprompt -alias startcom.ca.sub.class3 -file sub.class3.server.ca.crt
     keytool -import -trustcacerts -keystore $JAVA_HOME/jre/lib/security/jssecacerts -storepass changeit -noprompt -alias startcom.ca.sub.class4 -file sub.class4.server.ca.crt
fi

# Remove downloaded certs
rm -f ca.crt sub.class1.server.ca.crt sub.class2.server.ca.crt sub.class3.server.ca.crt sub.class4.server.ca.crt
</code>
NOTA: Requiere wget y el usuario root.