/**
  * Adds a new provider, at a specified position. The position is the preference order in which
  * providers are searched for requested algorithms. Note that it is not guaranteed that this
  * preference will be respected. The position is 1-based, that is, 1 is most preferred, followed
  * by 2, and so on.
  *
  * <p>If the given provider is installed at the requested position, the provider that used to be
  * at that position, and all providers with a position greater than <code>position</code>, are
  * shifted up one position (towards the end of the list of installed providers).
  *
  * <p>A provider cannot be added if it is already installed.
  *
  * <p>First, if there is a security manager, its <code>checkSecurityAccess</code> method is called
  * with the string <code>"insertProvider."+provider.getName()</code> to see if it's ok to add a
  * new provider. If the default implementation of <code>checkSecurityAccess</code> is used (i.e.,
  * that method is not overriden), then this will result in a call to the security manager's <code>
  * checkPermission</code> method with a <code>
  * SecurityPermission("insertProvider."+provider.getName())</code> permission.
  *
  * @param provider the provider to be added.
  * @param position the preference position that the caller would like for this provider.
  * @return the actual preference position in which the provider was added, or -1 if the provider
  *     was not added because it is already installed.
  * @throws NullPointerException if provider is null
  * @throws SecurityException if a security manager exists and its <code>{@link
  *          java.lang.SecurityManager#checkSecurityAccess}</code> method denies access to add a
  *     new provider
  * @see #getProvider
  * @see #removeProvider
  * @see java.security.SecurityPermission
  */
 public static synchronized int insertProviderAt(Provider provider, int position) {
   String providerName = provider.getName();
   check("insertProvider." + providerName);
   ProviderList list = Providers.getFullProviderList();
   ProviderList newList = ProviderList.insertAt(list, provider, position - 1);
   if (list == newList) {
     return -1;
   }
   Providers.setProviderList(newList);
   return newList.getIndex(providerName) + 1;
 }
 /**
  * Removes the provider with the specified name.
  *
  * <p>When the specified provider is removed, all providers located at a position greater than
  * where the specified provider was are shifted down one position (towards the head of the list of
  * installed providers).
  *
  * <p>This method returns silently if the provider is not installed or if name is null.
  *
  * <p>First, if there is a security manager, its <code>checkSecurityAccess</code> method is called
  * with the string <code>"removeProvider."+name</code> to see if it's ok to remove the provider.
  * If the default implementation of <code>checkSecurityAccess</code> is used (i.e., that method is
  * not overriden), then this will result in a call to the security manager's <code>checkPermission
  * </code> method with a <code>SecurityPermission("removeProvider."+name)</code> permission.
  *
  * @param name the name of the provider to remove.
  * @throws SecurityException if a security manager exists and its <code>{@link
  *          java.lang.SecurityManager#checkSecurityAccess}</code> method denies access to remove
  *     the provider
  * @see #getProvider
  * @see #addProvider
  */
 public static synchronized void removeProvider(String name) {
   check("removeProvider." + name);
   ProviderList list = Providers.getFullProviderList();
   ProviderList newList = ProviderList.remove(list, name);
   Providers.setProviderList(newList);
 }