Summary of experience in using intern() method in JAVA

Generally we rarely use the intern method. Today I will explain what this method does and what it is used for.

First of all, please look at an example:

[java] view plain copy
 print?
public static void main(String[] args) throws Exception {  
    String a =  "b" ;   
    String b =  "b" ;   
      
    System.out.print( a == b);   
      
    String c = "d" ;  
    String d = new String( "d" ).intern() ;   
    System.out.println( c == d);  
}

Can you see the message printed on the console in this example? The results output by the console here are all true true, because the intern method returns the normalized representation of the stringobject. When the intern method is called, if the pool has Contains a string equal to this String object (as determined by the equals(Object) method), returns the string in the pool. Otherwise, this String object is added to the pool, and a reference to this String object is returned. At this time c and d are equal.

Let’s look at an example:

[java] view plain copy
 print?
<span style="white-space:pre">      </span>String s1 = "ab123" ;  
        String s2 = new String( "ab123" ) ;  
        System.out.println( s1 == s2 );   
        String s3 = s2.intern() ;   
        System.out.println( s1 == s3 ) ;

Look at what is output here. I think everyone should understand what this method does! !

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