import java.lang.reflect.Field; import java.lang.reflect.Modifier; import java.util.*; /* You can check size of any object. Here I have just get the size of object in list and map Some warning is coming so ignore them */ public class Program { private static int REFERENCE_SIZE = 0; private static int HEADER_SIZE = 0; private static final int LONG_SIZE = 8; private static final int INT_SIZE = 4; private static final int BYTE_SIZE = 1; private static final int BOOLEAN_SIZE = 1; private static final int CHAR_SIZE = 2; private static final int SHORT_SIZE = 2; private static final int FLOAT_SIZE = 4; private static final int DOUBLE_SIZE = 8; private static final int ALIGNMENT = 8; static { try { if (System.getProperties().get("java.vm.name").toString().contains("64")) { //java.vm.name is something like "Java HotSpot(TM) 64-Bit Server VM" REFERENCE_SIZE = 8; HEADER_SIZE = 16; } else { REFERENCE_SIZE = 4; HEADER_SIZE = 8; } } catch (Exception ex) { //ex.printStackTrace(); //throw new AssertionError(ex); } } public static void main(String[] args) { Student s = new Student(7920723, "AJ"); Map> map = new HashMap<>(); List list1 = new ArrayList(); list1.add(new Student(7920723, "AJ")); list1.add(new Student(5818712, "Avinash")); list1.add(new Student(7920723, "Anant - MySelf")); map.put(1, list1); map.put(3, getAIMUMemberList()); try { System.out.println("Size Of Class Object = " + sizeOf(s)); System.out.println("Size Of List = " + sizeOf(list1)); System.out.println("Size of Map = " + sizeOf(map)); } catch (Exception e) { } } public static List getAIMUMemberList() { List list3 = new ArrayList(); list3.add(new Student(11066727, "Tanay - Thekedar")); list3.add(new Student(8843885, "Mr. Jaiswal - CEO")); list3.add(new Student(9233826, "Satnam Singh")); list3.add(new Student(14955296, "Abhay Pratap Singh")); list3.add(new Student(12077304, "Mr. King - Vice President")); list3.add(new Student(2837684, "Shubham Verma")); list3.add(new Student(14875620, "Virat Kohli")); list3.add(new Student(15771326, "Vinay_GB")); list3.add(new Student(11186837, "Alpha5&5")); list3.add(new Student(14676348, "Omega™")); list3.add(new Student(14669031, "Sir Arjun Verma")); list3.add(new Student(12052039, "Sam (I am Saikh)")); return list3; } public static long sizeOf(Object o) throws IllegalAccessException { return sizeOf(o, new HashSet()); } private static long sizeOf(Object o, Set visited) throws IllegalAccessException { if (o == null) { return 0; } ObjectWrapper objectWrapper = new ObjectWrapper(o); if (visited.contains(objectWrapper)) { //We have reference graph with cycles. return 0; } visited.add(objectWrapper); long size = HEADER_SIZE; Class clazz = o.getClass(); if (clazz.isArray()) { if (clazz == long[].class) { long[] objs = (long[]) o; size += objs.length * LONG_SIZE; } else if (clazz == int[].class) { int[] objs = (int[]) o; size += objs.length * INT_SIZE; } else if (clazz == byte[].class) { byte[] objs = (byte[]) o; size += objs.length * BYTE_SIZE; } else if (clazz == boolean[].class) { boolean[] objs = (boolean[]) o; size += objs.length * BOOLEAN_SIZE; } else if (clazz == char[].class) { char[] objs = (char[]) o; size += objs.length * CHAR_SIZE; } else if (clazz == short[].class) { short[] objs = (short[]) o; size += objs.length * SHORT_SIZE; } else if (clazz == float[].class) { float[] objs = (float[]) o; size += objs.length * FLOAT_SIZE; } else if (clazz == double[].class) { double[] objs = (double[]) o; size += objs.length * DOUBLE_SIZE; } else { Object[] objs = (Object[]) o; for (int i = 0; i < objs.length; i++) { size += sizeOf(objs[i], visited) + REFERENCE_SIZE; } } size += INT_SIZE; } else { Field[] fields = o.getClass().getDeclaredFields(); for (int i = 0; i < fields.length; i++) { if (Modifier.isStatic(fields[i].getModifiers())) { continue; } fields[i].setAccessible(true); String fieldType = fields[i].getGenericType().toString(); if (fieldType.equals("long")) { size += LONG_SIZE; } else if (fieldType.equals("int")) { size += INT_SIZE; } else if (fieldType.equals("byte")) { size += BYTE_SIZE; } else if (fieldType.equals("boolean")) { size += BOOLEAN_SIZE; } else if (fieldType.equals("char")) { size += CHAR_SIZE; } else if (fieldType.equals("short")) { size += SHORT_SIZE; } else if (fieldType.equals("float")) { size += FLOAT_SIZE; } else if (fieldType.equals("double")) { size += DOUBLE_SIZE; } else { size += sizeOf(fields[i].get(o), visited) + REFERENCE_SIZE; } } } if ((size % ALIGNMENT) != 0) { size = ALIGNMENT * (size / ALIGNMENT) + ALIGNMENT; } return size; } private static final class ObjectWrapper { private Object object; public ObjectWrapper(Object object) { this.object = object; } public boolean equals(Object obj) { if (obj == this) { return true; } if ((obj == null) || (obj.getClass() != ObjectWrapper.class)) { return false; } return object == ((ObjectWrapper) obj).object; } public int hashCode() { int hash = 3; hash = 47 * hash + System.identityHashCode(object); return hash; } } } public class Student { private int id; private String name; public Student(int id, String name) { this.id = id; this.name = name; } public void setId(int id) { this.id = id; } public int getId() { return id; } public void setName(String name) { this.name = name; } public String getName() { return name; } }

Object Size Calculator