JAVAオブジェクトのメモリ使用方法のテスト
1336 ワード
依存JARパッケージ:SizeOf.jar
http://sourceforge.net/projects/sizeof java.SizeOf is a simple java agent what can be used to calculate the memory size of java objects.
VM運転パラメータ:-javaagent:G:SizeOf.jar
start the jvm with the argument: -javaagent:/SizeOf.jar
出力:
http://sourceforge.net/projects/sizeof java.SizeOf is a simple java agent what can be used to calculate the memory size of java objects.
VM運転パラメータ:-javaagent:G:SizeOf.jar
start the jvm with the argument: -javaagent:
public class HeapSize {
/**
* @param args
*/
public static void main(String[] args) {
HashMap<Object, Object> map = new HashMap<Object, Object>();
// SizeOf.turnOnDebug();
String a = "a";
System.out.println("a:" + SizeOf.humanReadable(SizeOf.deepSizeOf(a)));
String size = SizeOf.humanReadable(SizeOf.deepSizeOf(map));
System.out.println("map size: " + size);
ArrayList<Object> list = new ArrayList<Object>();
size = SizeOf.humanReadable(SizeOf.deepSizeOf(list));
System.out.println("list size: " + size);
HashSet<Object> set = new HashSet<Object>();
size = SizeOf.humanReadable(SizeOf.deepSizeOf(set));
System.out.println("set size: " + size);
}
}出力:
JAVAGENT: call premain instrumentation for class SizeOf
a:88.0b
map size: 128.0b
list size: 80.0b
set size: 160.0b