自動(dòng)裝箱、自動(dòng)拆箱

1.自動(dòng)裝箱

Object obj = 3;
//相當(dāng)于Object obj = new Integer(3);
System.out.println(obj);

2.自動(dòng)拆箱

double d = new Double(3.14);
//相當(dāng)于double d = new Double(3.14).doubleValue();
System.out.println(d);