question: returns the single instance , creating one if it 's the first time this method is called . concode_field_sep List<String> mruFileList concode_elem_sep MRUDesignFile instance concode_elem_sep EventListenerList listenerList concode_elem_sep int MAX_SIZE concode_elem_sep String MRU_FILE_LIST_PROPERTY concode_field_sep List<String> getMRUFileList concode_elem_sep void setMRUFileList concode_elem_sep void firePropertyChange concode_elem_sep Preferences getPreferences concode_elem_sep void removeFile concode_elem_sep void clear concode_elem_sep void retrieve concode_elem_sep String getLastEditedDesignFile concode_elem_sep void store concode_elem_sep void removePropertyChangeListener concode_elem_sep void addPropertyChangeListener concode_elem_sep void addFile
target: MRUDesignFile function ( ) { return instance ; }