Java 中 byte/Integer 数组的实际数据大小是多少
Whats is the actual data size of an byte/Integer array in Java
我的问题是一个非常基础的问题，但我仍然很难完全理解它：
我的任务是发送一个包含 512 字节随机数据的 UDP 数据包 (Java)。所以这等于 4096 位。如果我发送一个大小为 4096 的字节数组（填充为“0”），是否等于 512 字节？
非常感谢:)
我在这里发现了一篇有趣的文章：dzone.com
以下是重要部分：
How to calculate memory usage of a Java object?: Very simplified explanation of how one could calculate a memory of any Java object. For example, lets say, you want to calculate the memory of a Java object which holds two int variables, one boolean variable, one Long object, and a reference to other objects. The memory would turn out to be following:
8 bytes for the object header
2 x 4 = 8 bytes for two int variables
1 byte for a boolean variable
8 bytes (object reference) + 8 bytes for long data type = 16 bytes for long object
4 bytes for reference to some other object
The total size of the above mentioned object will be 8 + 8 + 1 + 16 + 4 = 37 bytes + 3 bytes (for padding) = 40 bytes.
How to calculate memory usage of a Java array?: The page presents examples on how to calculate size of a Java array object.
For example, lets say a Java array consisting of 20 Integer objects. Following is the detail on the size:
12 bytes for array header object (8 bytes for header and 4 bytes for storing length of the array) ==> 20 x 16 bytes = 320 bytes for integer objects.
我的问题是一个非常基础的问题，但我仍然很难完全理解它：
我的任务是发送一个包含 512 字节随机数据的 UDP 数据包 (Java)。所以这等于 4096 位。如果我发送一个大小为 4096 的字节数组（填充为“0”），是否等于 512 字节？
非常感谢:)
我在这里发现了一篇有趣的文章：dzone.com
以下是重要部分：
How to calculate memory usage of a Java object?: Very simplified explanation of how one could calculate a memory of any Java object. For example, lets say, you want to calculate the memory of a Java object which holds two int variables, one boolean variable, one Long object, and a reference to other objects. The memory would turn out to be following:
8 bytes for the object header
2 x 4 = 8 bytes for two int variables
1 byte for a boolean variable
8 bytes (object reference) + 8 bytes for long data type = 16 bytes for long object
4 bytes for reference to some other object
The total size of the above mentioned object will be 8 + 8 + 1 + 16 + 4 = 37 bytes + 3 bytes (for padding) = 40 bytes.
How to calculate memory usage of a Java array?: The page presents examples on how to calculate size of a Java array object.
For example, lets say a Java array consisting of 20 Integer objects. Following is the detail on the size: 12 bytes for array header object (8 bytes for header and 4 bytes for storing length of the array) ==> 20 x 16 bytes = 320 bytes for integer objects.