java常量池

package 测试常量;

public class Test {
public static void main(String[] args){
String s1 = “hello world”;
String s2 = “hello world”;
System.out.println(s1==s2);

String s4 = new String(“你好”);
String s3 = “你好”;
System.out.println(s3==s4);

Integer i1 = 10;
Integer i2 = 10;
System.out.println(i1 == i2);

Integer i3 = 2000;
Integer i4 = 2000;
System.out.println(i3 == i4);

Integer i5 = new Integer(10);
Integer i6 = new Integer(10);
System.out.println(i5 == i6);

int i7 = 2000;
int i8 = 2000;
System.out.println(i7 == i8);

Double f1 = new Double(1.01);
Double f2 = new Double(1.01);
System.out.println(f1 == f2);

Double f3 = 1000.01;
Double f4 = 1000.01;
System.out.println(f3 == f4);

double f5 = 1000.01;
double f6 = 1000.01;
System.out.println(f5 == f6);
}
}

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输出结果是

true
false
true
false
false
true
false
false
true