I$\text{'}$m working in a route management system in Java, aimed at calculating and optimizing routes between different locations using algorithms and data structures. Each location will be represented as a node in an undirected graph, and connections between locations will be modeled as edges. These edges should have weight and time attributes. So I want to handle files in this project, meaning that the data inputted by the user should be stored. In conclusion, how can I implement file handling to save the data?

here's the code:

public class LocationManager implements Serializable $\{$

private static final long serialVersionUID $=1760598463252095534$L;

private int$[][]$ matrizAdyacencia;

private List locations;

public LocationManager$($int numLocations$)\{$

matrizAdyacencia $=$ new int$[$numLocations$][$numLocations$]$;

locations $=$ new ArrayList$<>()$;

$\}$

$/*$ public static LocationManager getInstance$()\{$

if $($manager$==$null$)$

manager$=$ new LocationManager$()$;

return manager;

$\}*/$

public int$[][]$ getAdjacencyMatrix$()\{$

return matrizAdyacencia;

$\}$

public void setAdjacencyMatrix$($int$[][]$ matrizAdyacencia$)\{$

this.matrizAdyacencia $=$ matrizAdyacencia;

$\}$

public List getLocations$()\{$

return locations;

$\}$

public void setLocations$($List locations$)\{$

this.locations $=$ locations;

$\}$

public void addLocation$($Location location$)\{$

locations.add$($location$)$;

$\}$

public void editLocation$($int index, Location location$)\{$

if $($index $>=0$ && index $<$ locations.size$())\{$

locations.set$($index$,$ location$)$;

$\}$

$\}$

public void deleteLocation$($int index$)\{$

if $($index $>=0$ && index $<$ locations.size$())\{$

locations.remove$($index$)$;

for $($int i $=$ index; i $<$ locations.size$()$; i$++)\{$

for $($int j $=0$; j $<$ matrizAdyacencia.length; j$++)\{$

matrizAdyacencia$[$i$][$j$]=$ matrizAdyacencia$[$i $+1][$j$]$;

$\}$

for $($int j $=0$; j $<$ matrizAdyacencia.length; j$++)\{$

matrizAdyacencia$[$j$][$i$]=$ matrizAdyacencia$[$j$][$i $+1]$;

$\}$

$\}$

$\}$

$\}$

public void addConnection$($int source, int destination, int weight$)\{$

if $($source $>=0$ && source $<$ locations.size$()$ &&

destination $>=0$ && destination $<$ locations.size$())\{$

matrizAdyacencia$[$source$][$destination$]=$ weight;

matrizAdyacencia$[$destination$][$source$]=$ weight; $//$ Assuming undirected graph

$\}$

$\}$

public List shortestPathDijkstra$($int start, int end$)\{$

int$[]$ dist $=$ new int$[$locations$.$size$()]$;

boolean$[]$ visited $=$ new boolean$[$locations$.$size$()]$;

int$[]$ parent $=$ new int$[$locations$.$size$()]$;

Arrays.fill$($dist$,$ Integer.MAX$\_$VALUE$)$;

dist$[$start$]=0$;

for $($int count $=0$; count $<$ locations.size$()-1$; count$++)\{$

int u $=$ minDistance$($dist$,$ visited$)$;

visited$[$u$]=$ true;

for $($int v $=0$; v $<$ locations.size$()$; v$++)\{$

if $(!$visited$[$v$]$ && matrizAdyacencia$[$u$][$v$]!=0$ &&

dist$[$u$]!=$ Integer.MAX$\_$VALUE &&

dist$[$u$]+$ matrizAdyacencia$[$u$][$v$]<$ dist$[$v$])\{$

dist$[$v$]=$ dist$[$u$]+$ matrizAdyacencia$[$u$][$v$]$;

parent$[$v$]=$ u;

$\}$

$\}$

$\}$

return getPath$($start$,$ end, parent$)$;

$\}$

private int minDistance$($int$[]$ dist, boolean$[]$ visited$)\{$

int min $=$ Integer.MAX$\_$VALUE;

int minIndex $=-1$;

for $($int i $=0$; i $<$ locations.size$()$; i$++)\{$

if $(!$visited$[$i$]$ && dist$[$i$]<$ min$)\{$

min $=$ dist$[$i$]$;

minIndex $=$ i;

$\}$

$\}$

return minIndex;

$\}$

private List getPath$($int start, int end, int$[]$ parent$)\{$

List path $=$ new ArrayList$<>()$;

for $($int at $=$ end; at $!=$ start; at $=$ parent$[$at$])\{$

path.add$($locations$.$get$($at$))$;

$\}$

path.add$($locations$.$get$($start$))$;

Collections.reverse$($path$)$;

return path;

$\}$

$($all the other methods $($algorithm of Dijkstra and others$)$ are omitted because the space$)$

public void displayMenu$()\{$

System.out.println$("$Route Management System Menu:"$)$;

System.out.println$("1.$ Add Location"$)$;

System.out.println$("2.$ Edit Location"$)$;

System.out.println$("3.$ Delete Location"$)$;

System.out.println$("4.$ Calculate Shortest Path $($Dijkstra$\text{'}$s Algorithm$)")$;

System.out.println$("5.$ Find Minimum Spanning Tree $($Prim$\text{'}$s Algorithm$)")$;

System.out.println$("6.$ Find Minimum Spanning Tree $($Kruskal$\text{'}$s Algorithm$)")$;

System.out.println$("7.$ Find Shortest Path Matrix $($Floyd$-$Warshall Algorithm$)")$;

System.out.println$($