英文:
2 String object have same address
问题
这是根据Java8版本。
String s = "Hello1";
String ab1 = new String(s);
String ab2 = new String(s);
System.out.println("s = " + s.hashCode());
System.out.println("ab1 = " + ab1.hashCode());
System.out.println("ab2 = " + ab2.hashCode());
输出结果如下：
s = -2137068097
ab1 = -2137068097
ab2 = -2137068097
变量 s 应该在字符串池中，
ab1 和 ab2 在堆中，具有不同的地址，作为不同的对象。
但是所有三者都得到了相同的地址。
英文:
This is as per Java8
String s = "Hello1";
String ab1 = new String(s) ;
String ab2 = new String(s) ;
System.out.println("s = " + s.hashCode());
System.out.println("ab1 = " + ab1.hashCode());
System.out.println("ab2 = " + ab2.hashCode());
output is coming as
s = -2137068097
ab1 = -2137068097
ab2 = -2137068097
s should be on String pool
ab1 and ab2 is on heap with different address as different object
but all 3 got same address
答案1
得分: 2
HashCode不是堆地址或内存位置。查看String hashCode的实现
public int hashCode() {
int h = hash;
if (h == 0 && value.length > 0) {
char val[] = value;
for (int i = 0; i < value.length; i++) {
h = 31 * h + val[i];
}
hash = h;
}
return h;
}
因此，对于长度相同且经过ASCII转换后相加返回相同值的值，将得到相同的哈希码。
英文:
HashCode is not Heap Address/memory Location. <br>
Have a look at String hashCode implementation
public int hashCode() {
int h = hash;
if (h == 0 && value.length > 0) {
char val[] = value;
for (int i = 0; i < value.length; i++) {
h = 31 * h + val[i];
}
hash = h;
}
return h;
}
Hence for same length value & value whose ascii conversion and then addition returns same value gives same hashcode.
答案2
得分: 0
以下是翻译好的内容：
哈希码并非实际的内存地址值。为了证明这一点，我们可以在所有三种变量组合上使用 == 运算符。所有三种情况都返回 false，以确认它们的内存地址不同。
System.out.println(s == ab1);
System.out.println(ab1 == ab2);
System.out.println(s == ab2);
英文:
The hashcode is not the actual memory address value. To prove this, we can use the == operator on the all three combination of variables. All three gives false as to confirm that the memory address are not the same for them.
System.out.println(s == ab1);
System.out.println(ab1 == ab2);
System.out.println(s == ab2);
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