Java UnsafeÀàÀí½â

public class UnsafeTest {
    private int i;

    public int getI() {
        return i;
    }

    public void setI(int i) {
        this.i = i;
    }

    public static void main(String[] args) throws NoSuchFieldException {
        UnsafeTest unsafeTest = new UnsafeTest();
        Unsafe unsafe = null;

        try {
            Class<Unsafe> unsafeClass = Unsafe.class;
            Field theUnsafe = unsafeClass.getDeclaredField("theUnsafe");
            theUnsafe.setAccessible(true);
            unsafe = (Unsafe) theUnsafe.get(unsafeClass);
        }catch (Exception e) {

        }
        long offset = unsafe.objectFieldOffset(UnsafeTest.class.getDeclaredField("i"));
        unsafe.putInt(unsafeTest, offset, 2);
        System.out.println(unsafeTest.getI());
    }
}