The difference between string s= "abc" and string S=new string ("abc")

First, explain the difference between string s= "abc" and string S=new string ("abc"):

String s= "ABC"; the object is not created in the heap, the constant "abc" is first searched for in the constant pool, and if there is no "ABC", the ABC is stored in the Run-time pool, then the reference is assigned to S, and the existing address is assigned to s if there is a direct value.

String S=new string ("abc"), first creating an object in the heap, and then assigning the object reference to S.

Next look at this small example:

public class Example {
    String str = new String ("good");
    String str1 = "good";
    String str2 = "good";
    public static void Main (string[] args) {
        Example Example = new Example ();
        System.out.println (EXAMPLE.STR==EXAMPLE.STR1);//output to False
        System.out.println (EXAMPLE.STR2==EXAMPLE.STR1); Output is True
    }
 }

Inside This example:

STR holds a reference to memory in the heap, str1 as an address in a constant pool;

When executing the str2= "good", it will look for "good" directly in the constant pool, if there is a constant, directly assign the constant address to str2, if there is no "good", you need to add it to the constant pool, and then add the new constant address to str2.

The string object also has a method--intern (unfortunately, it is a local method and cannot see how it is implemented internally):

This method can be dynamically extended to run a regular volume pool.