difference between string literal and string object

来源：互联网发布：剑三叶英捏脸数据编辑：程序博客网时间：2024/05/14 07:10

new String("text"); explicitly creates a new and referentially distinct instance of a String object;

String s = "text"; may reuse an instance from the string constant pool if one is available.

You very rarely would ever want to use the new String(anotherString) constructor.

From the API:

String(String original) : Initializes a newly created String object so that it represents the same sequence of characters as the argument; in other words, the newly created string is a copy of the argument string. Unless an explicit copy of original is needed, use of this constructor is unnecessary since strings are immutable.

Whenever you call new in JAVA it create an object in heap and obviously it will call the constructor also.
String literals will go into String Constant Pool.
It might help you to understand it visually to remember it for longer time.

Whenever you call new in JAVA it create an object in heap and obviously it will call the constructor also.
String literals will go into String Constant Pool.
It might help you to understand it visually to remember it for longer time.
Object creation line by line:
String str1 = new String("java5");
Using string literal "java5" in the constructor, an new string value is stored in string constant pool
Using new operator a new string object is created in the heap with "java5" as value
String str2 = "java5
Reference str2 is pointed to already stored value in string constant pool
String str3 = new String(str2);
A new string object is created in the heap with the same value as reference by str2
String str4 = "java5";
Reference str4 is pointed to already stored value in string constant pool
Total objects : Heap[堆] - 2, Constant Pool[常量池] - 1

Whenever you call new in JAVA it create an object in heap and obviously it will call the constructor also.
String literals will go into String Constant Pool.

It might help you to understand it visually to remember it for longer time.

enter image description here

Object creation line by line:

String str1 = new String("java5");
- Using string literal "java5" in the constructor, an new string value is stored in string constant pool
- Using new operator a new string object is created in the heap with "java5" as value
String str2 = "java5
- Reference str2 is pointed to already stored value in string constant pool
String str3 = new String(str2);
- A new string object is created in the heap with the same value as reference by str2
String str4 = "java5";
- Reference str4 is pointed to already stored value in string constant pool

Total objects : Heap - 2, Pool - 1

0 0