code: public final boolean
          entryInstanceOf(String alias,
                          Class<? extends KeyStore.Entry> entryClass)
          throws KeyStoreException
      {
  
          if (alias == null || entryClass == null) {
              throw new NullPointerException("invalid null input");
          }
          if (!initialized) {
              throw new KeyStoreException("Uninitialized keystore");
          }
          return keyStoreSpi.engineEntryInstanceOf(alias, entryClass);
      }
docs: Determines if the keystore <code>Entry</code> for the specified
  <code>alias</code> is an instance or subclass of the specified
  <code>entryClass</code>.
  
  @param alias the alias name
  @param entryClass the entry class
  
  @return true if the keystore <code>Entry</code> for the specified
  <code>alias</code> is an instance or subclass of the
  specified <code>entryClass</code>, false otherwise
  
  @exception NullPointerException if
  <code>alias</code> or <code>entryClass</code>
  is <code>null</code>
  @exception KeyStoreException if the keystore has not been
  initialized (loaded)
  
  @since 1.5