Memory Size of an object as byte

Faraz :

If I have an object, for example...

String city = "Chicago"

and I have millions of them. Let's say I take the byte of those million objects,

byte[] cityByte = "Chicago".getBytes()

Would byte take less space in memory?

edit: more in-depth:

I have several com.microsoft.azure.servicebus.Message objects. I intend to use SerializationUtils from Apache Commons Lang to get the byte array of each object and store it in a List.

I was thinking that if I store 1 million Message objects in a List, that might cause an issue. But if I store the same million objects as a byte array in a List, I will have a little more memory left so I can do other stuff. Hence the question.

Matthew I. :

I used JOL1 to determine the actual size of the objects in memory at runtime:

import org.openjdk.jol.info.GraphLayout;

public class MainClass {

    public static void main(String[] args) {

        String city = "Chicago";

        byte[] cityByte = "Chicago".getBytes();

        System.out.println(GraphLayout.parseInstance(city).toPrintable());
        System.out.println(GraphLayout.parseInstance(cityByte).toPrintable());
    }
}

output:

java.lang.String@4d7e1886d object externals:
          ADDRESS       SIZE TYPE             PATH                           VALUE
        76ac826d8         24 java.lang.String                                (object)
        76ac826f0         32 [C               .value                         [C, h, i, c, a, g, o]


[B@3caeaf62d object externals:
          ADDRESS       SIZE TYPE PATH                           VALUE
        76ac82738         24 [B                                  [67, 104, 105, 99, 97, 103, 111]

Conclusion: 'String' 32 bytes VS 'byte[]' 24 bytes

P.S. Results may vary depends on JVM version and options. Try the same approach in your environment. Run at jdk_1.8.0_161 Mac OS 10.14

JOL