浅谈JAVA内存分配与参数传递

class BirthDate{
 private int day;
 private int month;
 private int year;
 public BirthDate(int d,int m,int y){
 day=d;
 month=m;
 year=y;
 }
}

public class Test{
 public static void main(String[] args){
 int date=9;
 Test test=new Test();
 test.change(date);
 BirthDate d1=new BirthDate(7,7,1970);
 }
 
 public void change(int i){
 i=1234;
 }
}

public class TestTransfer{
 public static void main(String[] args){
 int a=6;
 int b=9;
 swap(a,b);
 System.out.println("交换结束后，a的值是"+a+";b的值是"+b); //a=9，b=6
 }
 
 public static void swap(int a,int b){
 int tmp=a;
 a=b;
 b=tmp;
 System.out.println("swap方法里，a的值是"+a+";b的值是"+b); //a=6,b=9
 }
}

public class TestTransfer{
 public static void main(String[] args){
 DataSwap ds=new DataSwap();
 ds.a=6;
 ds.b=9;
 swap(ds);
 System.out.println("交换结束后，ds.a的值是"+ds.a+";ds.b的值是"+ds.b); //a=9,b=6
 }
 
 public static void swap(DataSwap ds){
 int tmp=ds.a;
 ds.a=ds.b;
 ds.b=tmp;
 System.out.println("swap方法里，ds.a的值是"+ds.a+";ds.b的值是"+ds.b); //a=9,b=6
 }
}
 
class DataSwap{
 public int a;
 public int b;
}