package does not exist error

I have a playframework project where I access some packages from rt.jar

I use jdk 1.8.0 u77

The packages are the following:

import java.security.cert.X509Certificate;
import sun.security.tools.keytool.CertAndKeyGen;
import sun.security.x509.X500Name;
import sun.security.pkcs10.*

but for the imports below I get  a package  does not exist error, which can't be true because they do exist in rt.jar

sun.security.tools.keytool.CertAndKeyGen
sun.security.pkcs10.*

Error:(6, -1) Play 2 Compiler: 
 C:\user\projects\portal\app\com\example\security\cert\X509Cert.java:6: package sun.security.pkcs10 does not exist
 import sun.security.pkcs10.*;
 C:\user\projects\portal\app\com\v\security\cert\GenerateCSR.java:75: cannot find symbol