Can anyone please tell me what does the hashCode() method of String class contain?

Question

and what kind of value it returns. in a normal class, if I call hashCode() method it returns the address of the object in decimal format. But for string class it is different. can anyone please explain it to me.

Answer 1

"The value 31 was chosen because it is an odd prime. If it were even and the multiplication overflowed, information would be lost, as multiplication by 2 is equivalent to shifting. The advantage of using a prime is less clear, but it is traditional. A nice property of 31 is that the multiplication can be replaced by a shift and a subtraction for better performance: 31 * i == (i << 5) - i. Modern VMs do this sort of optimization automatically."
From:
https://stackoverflow.com/questions/299304/why-does-javas-hashcode-in-string-use-31-as-a-multiplier
From From:
A book 😜

Answer 2

It returns the hashcode.

Hashcode is calculated by:

Quoted from Oracle:
"
s[0]*31^(n-1) + s[1]*31^(n-2) + ... + s[n-1]

using int arithmetic, where s[i] is the ith character of the string, n is the length of the string, and ^ indicates exponentiation. (The hash value of the empty string is zero.)"

Answer 3

and why 31? why not other number?

Answer 4

thnx