question: public void addExtension ( String extension ) { if ( filters == null ) { filters = new Hashtable < String , ExampleFileFilter > ( 5 ) ; } if ( extension != null ) { filters . put ( extension . toLowerCase ( ) , this ) ; } fullDescription = null ; }
target:  Adds a filetype "dot" extension to filter against. For example: the following code will create a filter that filters out all files except those that end in ".jpg" and ".tif": ExampleFileFilter filter = new ExampleFileFilter(); filter.addExtension("jpg"); filter.addExtension("tif"); Note that the before the extension is not needed and will be ignored.