Question

Have I correctly added an element to a hashTable?

Flows flows = new Flows(sIP,dIP);
FlowStatics flowStatics = new FlowStatics(packetLength,timeArrival);

HashMap myHashMap = new HashMap<Flows, FlowStatics>();
myHashMap.put(flows, flowStatics);

Answer 1

To avoid compiler warnings, code it like this:

HashMap<Flows, FlowStatics> myHashMap = new HashMap<Flows, FlowStatics>();
myHashMap.put(flows, flowStatics);

If you don’t parametrize the myHashMap variable, then you can’t add in the second line without getting warnings.

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Here is working example on how to ‘print’ some hashmap statistics:

HashMap<Flows, FlowStatics> myHashMap = new HashMap<Flows, FlowStatics>();
for (int i = 0; i < 10; i++) {
  // OP commented that the map is populated in a loop
  myHashMap.put(createNewFlow(), createNewFlowStatistics());  // populate map
}
System.out.printf("Number of items in Map: %s%n", myHashMap.keyset().size());

(OP asked for adivice in a comment to another answer)