Type Reason Javax.Security.Cert.CertificateExpiredException if the certificate has expired. Javax.Security.Cert.CertificateNotYetValidException if the certificate is not yet valid. 
Checks whether the certificate is currently valid.
The validity defined in ASN.1:
java Example
 validity             Validity
 Validity ::= SEQUENCE {
      notBefore       CertificateValidityDate,
      notAfter        CertificateValidityDate }
 CertificateValidityDate ::= CHOICE {
      utcTime         UTCTime,
      generalTime     GeneralizedTime }