importjava.lang.management.ManagementFactory;importjava.lang.management.MemoryMXBean;publicclassObjectSizeFetcher{privatestaticMemoryMXBeanmemoryMXBean;static{memoryMXBean=ManagementFactory.getMemoryMXBean();}publicstaticlonggetObjectSize(Objectobject){memoryMXBean.gc();returnmemoryMXBean.getObjectPendingFinalization...
AI检测代码解析 importsun.misc.Unsafe;importjava.lang.reflect.Field;publicclassObjectSizeFetcher{privatestaticUnsafeunsafe;publicstaticvoidmain(String[]args)throwsException{Fieldf=Unsafe.class.getDeclaredField("theUnsafe");f.setAccessible(true);unsafe=(Unsafe)f.get(null);longsize=getObjectSize(newYourObjec...
packagesizeof;importjava.lang.instrument.Instrumentation;publicclassObjectShallowSize {privatestaticInstrumentation inst;publicstaticvoidpremain(String agentArgs, Instrumentation instP){ inst=instP; }publicstaticlongsizeOf(Object obj){returninst.getObjectSize(obj); } } 定义META-INF/MANIFEST.MF文件 Premain-...
Size(ObjectA) = Size(对象头(_mark)) + size(oop指针) + size(数据区) Size(ObjectA) = 8 + 4 + 4(String) + 4(int) + 1(byte) + 1(byte) + 2(padding) + 4(int) + 4(ObjectB指针) + 1(byte) + 7(padding) Size(ObjectA) = 40 我们直接通过两种获取java对象内存占用大小的方式来...
public double getFromByteSize(long byteSize) { return byteSize*1.0/1024/1024/1024; } }; public abstract double getFromByteSize(long byteSize); } /** * 默认 * 返回bytes * @param o * @return */ public static double getObjectSize(Object o,SizeEnum sizeEnum){ ...
Premain-class: pac.testcase.utils.ObjectSizeUtils Can-Redefine-Classes: false 1. 2. 随便写一个实体类,用来测试: AI检测代码解析 classPerson{privateStringname;privateStringlife;publicStringgetName(){returnname;}publicvoidsetName(Stringname){=name;}publicStringgetLife(){returnlife;}publicvoidsetLife(...
public class InstrumentationExample { public static void printObjectSize(Object object) { System.out.println("Object type: " + object.getClass() + ", size: " + InstrumentationAgent.getObjectSize(object) + " bytes"); } public static void main(String[] arguments) { String emptyString = ""...
Size of any Object reference */20privatestaticfinal int objectRefSize;21static{22try{23Field field=Unsafe.class.getDeclaredField("theUnsafe");24field.setAccessible(true);25unsafe=(Unsafe)field.get(null);2627// 可以通过Object[]数组得到oop指针究竟是压缩后的4个字节还是未压缩的8个字节28objectRef...
实现一个sizeof获取Java对象大小 由于Java的设计者不想让程序员管理和了解内存的使用,我们想要知道一个对象在内存中的大小变得比较困难了。本文提供了可以获取对象的大小的方法,但是由于各个虚拟机在内存使用上可能存在不同,因此该方法不能在各虚拟机上都适用,而是仅在hotspot 32位虚拟机上,或者其它内存管理方式与...
The Graal team is pleased to announce the general availability of Oracle GraalVM for JDK 23. In addition to JDK 23 support, this release includes many enhancements to Native Image ahead-of-time compilation to tune a generated executable’s size, memory usage, and throughput. This release is al...