Question

I want to use a hashtable to uniquely link immutable string IDs to mutable objects. If I have two strings of the same characters, will Java interpret them as different keys to the hash table? I know that Strings are objects, so two strings might not have the same reference.

In other words, if I do …

myHashTable.add("A" , ObjectA)
String myReference = "A" 
myHashTable.add(myReference, ObjectB) // I am not sure how java will interpret this
myHashTable.get("A") //returns A
myHashTable.get(myReference) //returns B
myReference.equals("A") //returns true

Can I safely use strings as keys to the hashtable (meaning that strings made up of the same characters will return the same value)

Answer 1

The String.hashCode() method is based only on the content of the string, not the object identity. So yes, this is safe.