What is the difference between Heap memory and string constant pool in java

Question

In Java

1. Object created using new operator will be stored in the heap memory.
2. The object created using string lit

Answer 1

It is not correct to compare heap and constant pool. Especially using hashCode.

Let's go step by step:

1. Since Java 7 string pool is inside the heap memory. Read more.

2. HashCode in Java is not related to memory address*

   JVM has an arg to specify hashCode default algorithm

   -XX:hashCode=k

   Number k could be one of:

   1. Park-Miller RNG
   2. foo(address, global state)
   3. 1 (const)
   4. incremental (++)
   5. address
   6. thread-local Xorshift (default in HotSpot, java 8)

3. String override default hashCode implementation. It is based on string content. java.lang.String:

   public int hashCode() {
       int h = hash;
       if (h == 0 && value.length > 0) {
           char val[] = value;
           for (int i = 0; i < value.length; i++) {
               h = 31 * h + val[i];
           }
           hash = h;
       }
       return h;
   }