Area: HotSpot
Synopsis: In JDK 7, interned strings are no longer allocated in the permanent generation of the Java heap, but are instead allocated in the main part of the Java heap (known as the young and old generations), along with the other objects created by the application. This change will result in more data residing in the main Java heap, and less data in the permanent generation, and thus may require heap sizes to be adjusted. Most applications will see only relatively small differences in heap usage due to this change, but larger applications that load many classes or make heavy use of the String.intern() method will see more significant differences.
RFE: 6962931

String a = "holten";
String b = "holten";

String a = new String("holtenObj");
String b = new String("holtenObj");

/**
 * Created by holten.gao on 2016/8/16.
 */
public class Main {
  public static void main(String[] args){
    String str1 = "高小天";
    String str2 = "高小天";
    System.out.println(str1==str2);//true
    
    String str3 = new String("高大天");
    String str4 = new String("高大天");
    System.out.println(str3==str4);//false
  }
}

true
false