Public static void main (String [] args) {
The StringBuilder sb=new StringBuilder (" ABC "); 
The update (sb); 
System. The out. Println (sb); 

} 
Public static void update (StringBuilder sb) {
Sb=new StringBuilder (" xyz "); 
System. The out. Println (sb); 
} 

 

Public static void main (String [] args) {
String STR="a, b, c"; 
The update (STR); 
System. The out. Println (STR); 
} 
Public static void, update (String STR) {
String STR="x, y, z" 
System. The out. Println (STR); 
} 

CodePudding user response:

Do not have what distinction, you can simply understand the difference between the String and the StringBuilder is roughly equal to the difference between arrays and collections

CodePudding user response:

From the standpoint of memory, if single
String is immutable, every time is in fact a new object, but a normal String a="213" that are references to the thread pool heap memory overhead is also good

But if the String a=new String (" 123 ") it is a waste of memory, recommend the StringBuilder