Java – how do I know how many objects will be created using the following code?

For strings, I'm a little confused about the object situation, so I want to know how many objects will be created with the following code, and give some explanations for string objects and heap creation of string objects

public static void main(String[] args) {

    String str1 = "String1";

    String str2 = new String("String1");

    String str3 = "String3";

    String str4 = str2 + str3;

    }

Solution

Four objects are created

Two notes:

>New string ("something") always creates a new object The string literal "something" creates only one object for all instances The best practice is never to use a new string ("something") – instantiation is redundant. > Concatenation of two strings is converted to StringBuilder Append (first) append(second). Tostring(), so create another object here