code: public final static String getDefaultType() {
          String cpvtype =
              AccessController.doPrivileged(new PrivilegedAction<String>() {
                  public String run() {
                      return Security.getProperty(CPV_TYPE);
                  }
              });
          return (cpvtype == null) ? "PKIX" : cpvtype;
      }
docs: Returns the default {@code CertPathValidator} type as specified by
  the {@code certpathvalidator.type} security property, or the string
  {@literal "PKIX"} if no such property exists.
  
  <p>The default {@code CertPathValidator} type can be used by
  applications that do not want to use a hard-coded type when calling one
  of the {@code getInstance} methods, and want to provide a default
  type in case a user does not specify its own.
  
  <p>The default {@code CertPathValidator} type can be changed by
  setting the value of the {@code certpathvalidator.type} security
  property to the desired type.
  
  @see java.security.Security security properties
  @return the default {@code CertPathValidator} type as specified
  by the {@code certpathvalidator.type} security property, or the string
  {@literal "PKIX"} if no such property exists.