Difference:
The empty string is an object that has been instantiated and has memory space, but the value stored in the memory space is empty; and null It represents an object that has not been instantiated and does not occupy memory space.
String aaa = "";//空串 String bbb=null; //null值
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For example:
public class HelloWorld { public static void main(String [] args){ System.out.println("hello world!"); // System.out.println(args[0]); String aaa = "lihuijuan"; String bbb =""; String ccc = null; // ccc.isEmpty(); System.out.println(aaa.isEmpty()); System.out.println(bbb.isEmpty()); System.out.println(ccc.isEmpty()); } }
Running result:
That is to say, the object bbb that refers to the empty string can call properties such as String's isEmpty(), but ccc cannot be called, which means that ccc does not actually point to any memory space.
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