``````import java.util.*;

public class Floyd {

private static final int INF = Integer.MAX_VALUE;

public static void main(String[] args) {
List<Edge> edges = new ArrayList<>();

/*
Graph with no negative weight cycles
>(1)
/  | \
2/     |  \3
/    |   \
(0)     |5   > (2)
\     |   /
8\  |  / 3
\ v /
>(3)<
|
|
>(4)
|
|
>(5)
*/

search(edges, 6, 0, 5);
System.out.println("------------------------------------------------------");
search(edges, 7, 0, 6);

System.out.println("\n####################################################");
System.out.println("Graph contains negative weight cycle");
System.out.println("####################################################\n");

edges.clear();

/*
Graph with no negative weight cycles
>(1)
/  A \
2/     |  \3
/    |   \
(0)     |-8   > (2)
\     |    /
8\  |   / 3
\ |  /
>(3)<
|
|
>(4)
|
|
>(5)
*/

search(edges, 6, 0, 5);
System.out.println("------------------------------------------------------");
search(edges, 7, 0, 6);
}

public static int search(List<Edge> edges, int n, int start, int end) {
Map<Integer, String> detailedPath = new HashMap<>();

detailedPath.put(start, start + "");

int[][] weights = new int[n][n];

// Initialized with largest integer which represents no direct path from point a to b.
for (int i = 0; i < n; i++) {
Arrays.fill(weights[i], INF);

weights[i][i] = 0;
}

for (Edge edge : edges) {
weights[edge.start][edge.end] = edge.weight;

if (edge.start == start) {
detailedPath.put(edge.end, start + "-->" + edge.end);
}
}

for (int interVertex = 0; interVertex < n; interVertex++) {

// walk to j from i through intermediate vertex interVertex

for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
if (i == interVertex || interVertex == j) {
continue;
}

int tmp = INF;

if (weights[i][interVertex] != INF && weights[interVertex][j] != INF) {
tmp = weights[i][interVertex] + weights[interVertex][j];
}

if (weights[i][j] > tmp) {
if (i == start) {
detailedPath.put(j, detailedPath.get(interVertex) + "-->" + j);
}

weights[i][j] = tmp;
}
}
}
}

boolean containsNegativeWeightCycle = false;

// check for negative-weight cycles.

// Floyd sorts out all the optimal paths for any vertex pairs including the path vertex to itself.
// So if there is a negative-weight cycle, path of vertex to itself is negative.
for (int i = 0; i < n; i++) {
if (weights[i][i] < 0) {
containsNegativeWeightCycle = true;

break;
}
}

if (containsNegativeWeightCycle) {
try {
throw new Exception("Graph contains negative weight cycle");
} catch (Exception e) {
e.printStackTrace();
}
} else if (weights[start][end] != INF) {
System.out.println("From " + start + " to " + end + ", the lowest weight path " + detailedPath.get(end) + ", total weight is " + weights[start][end]);
} else {
System.out.println("From " + start + " to " + end + ", no path exists");
}

return weights[start][end];
}

static class Edge {
int start = 0;
int end = 0;
int weight = 0;

public Edge(int start, int end, int weight) {
this.start = start;
this.end = end;
this.weight = weight;
}
}
}
``````