A hashcode is a number (object's memory address) generated from any object, not just strings. This number is used to store/retrieve objects quickly in a hashtable.
The syntax of the string hashCode()
method is:
string.hashCode()
Here, string is an object of the String
class.
hashCode() Parameters
The matches()
method doesn't take any parameters.
hashCode() Return Value
- returns the hashcode, which is an
int
value, of the string
The hash code is computed using formula:
s[0]*31(n-1) + s[1]*31(n-2) + ... + s[n-1]
where,
s[0]
is the first element of strings
,s[1]
is the second element and so on.n
is the length of the string
Example: Java String hashCode()
class Main {
public static void main(String[] args) {
String str1 = "Java";
String str2 = "Java Programming";
String str3 = "";
System.out.println(str1.hashCode()); // 2301506
System.out.println(str2.hashCode()); // 1377009627
// hash code of empty string is 0
System.out.println(str3.hashCode()); // 0
}
}
Note: For two strings to be equal, their hash code also must be equal.