java中打印变量地址

import sun.misc.Unsafe;import java.lang.reflect.Field;import java.util.Arrays;import java.util.Collections;public class OrderOfObjectsAfterGCMain {    static final Unsafe unsafe = getUnsafe();    static final boolean is64bit = true; // auto detect if possible.    public static void main(String... args) {        Double[] ascending = new Double[16];        for(int i=0;i<ascending.length;i++)            ascending[i] = (double) i;        Double[] descending = new Double[16];        for(int i=descending.length-1; i>=0; i--)            descending[i] = (double) i;        Double[] shuffled=new Double[16];        for(int i=0;i<shuffled.length;i++)            shuffled[i] = (double) i;        Collections.shuffle(Arrays.asList(shuffled));        System.out.PRintln("Before GC");        printAddresses("ascending", ascending);        printAddresses("descending", descending);        printAddresses("shuffled", shuffled);        System.gc();        System.out.println("/nAfter GC");        printAddresses("ascending", ascending);        printAddresses("descending", descending);        printAddresses("shuffled", shuffled);        System.gc();        System.out.println("/nAfter GC 2");        printAddresses("ascending", ascending);        printAddresses("descending", descending);        printAddresses("shuffled", shuffled);    }    public static void printAddresses(String label, Object... objects) {        System.out.print(label + ": 0x");        long last = 0;        int offset = unsafe.arrayBaSEOffset(objects.getClass());        int scale = unsafe.arrayIndexScale(objects.getClass());        switch (scale) {        case 4:            long factor = is64bit ? 8 : 1;            final long i1 = (unsafe.getInt(objects, offset) & 0xFFFFFFFFL) * factor;            System.out.print(Long.toHexString(i1));            last = i1;            for (int i = 1; i < objects.length; i++) {                final long i2 = (unsafe.getInt(objects, offset + i * 4) & 0xFFFFFFFFL) * factor;                if (i2 > last)                    System.out.print(", +" + Long.toHexString(i2 - last));                else                    System.out.print(", -" + Long.toHexString( last - i2));                last = i2;            }            break;        case 8:            throw new AssertionError("Not supported");        }        System.out.println();    }    private static Unsafe getUnsafe() {        try {            Field theUnsafe = Unsafe.class.getDeclaredField("theUnsafe");            theUnsafe.setaccessible(true);            return (Unsafe) theUnsafe.get(null);        } catch (Exception e) {            throw new AssertionError(e);        }    }}