Returns true if the named node exists. Accepts a relative or absolute pathname. Absolute pathnames (which begin with {@code '/'}) are interpreted relative to the root of this node. Relative pathnames (which begin with any character other than {@code '/'}) are interpreted relative to this node itself. The pathname {@code ""} is valid, and refers to thisnode itself.
If this node (or an ancestor) has already been removed with the {@link #removeNode()} method, it is legal to invoke this method,but only with the pathname {@code ""}; the invocation will return {@code false}. Thus, the idiom {@code p.nodeExists("")} may be used totest whether {@code p} has been removed.
@param pathName the path name of the node whose existence is to bechecked.
@return true if the specified node exists.
@throws BackingStoreException if this operation cannot be completed dueto a failure in the backing store, or inability to communicate with it.
@throws IllegalStateException if this node (or an ancestor) has beenremoved with the {@link #removeNode()} method and{@code pathname} is not the empty string ({@code ""}).
@throws IllegalArgumentException if the path name is invalid (i.e., itcontains multiple consecutive slash characters, or ends with a slash character and is more than one character long).