为何输出会出现乱码呢

为什么输出会出现乱码呢？
RT。这是我同学托我请教大家的。他在国外读computer science本科，学到java class部分（就是用class去写程序）
他之前写的那个运行正常 但为什么第二个写的就出现了问题呢？（能运行，但运行出来的结果是乱码，底下会贴出）。
这是他写的程序（每一个class对应一个类）
eclipse写的。

class eye
{
private int r;
public double pi() {return 3.1416;}
public eye(int r1)
{
r=r1;
}
public int getR(){return r;}
public void setR(int r1){r=r1;}
public boolean issmall(){return r>10;}
public boolean close(){return r==0;}
}

class mouth
{
private int w,h;
public double pi(){return 3.1416;}
public mouth(int w1,int h1)
{
w=w1;
h=h1;
}
public int getW(){return w;}
public int getH(){return h;}
public void setW(int w1){w=w1;}
public void setH(int h1){h=h1;}
public boolean isbig(){return w>10||h>5;}
public boolean close(){return w==0||h==0;}
}

class nose
{
private int x,y,z;
public nose(int x1,int y1,int z1)
{
x=x1;
y=y1;
z=z1;
}
public int getX(){return x;}
public int getY(){return y;}
public int getZ(){return z;}
public void setX(int x1){x=x1;}
public void setY(int y1){y=y1;}
public void setZ(int z1){z=z1;}
public boolean isbig(){return x>10||y>10||z>10;}
public boolean cut(){return x==0||y==0||z==0;}
}

class head
{
private int r;
private int w,h;
private int x,y,z;
private int numHair;
private int k;
eye le;
eye re;
nose n;
mouth m;
public head(int r1,int w1,int h1,int x1,int y1,int z1)
{
r=r1;
w=w1;
h=h1;
x=x1;
y=y1;
z=z1;
}
public head(int nu,int k1,eye le1,eye re1,nose n1,mouth m1)
{
numHair=nu;
k=k1;
le=le1;
re=re1;
n=n1;
m=m1;
}
public int getNumHair(){return numHair;}
public int getK(){return k;}
public eye getle(){return le;}
public eye getre(){return re;}
public nose getN(){return n;}
public mouth getM(){return m;}
public void setle(eye le1){le=le1;}
public void setre(eye re1){re=re1;}
public void setn(nose n1){n=n1;}
public void setm(mouth m1){m=m1;}
public void setNumHair(int nu){numHair=nu;}
public void setK(int k1){k=k1;}
public boolean isnormal(){return le.getR()==re.getR();}
public boolean headache(){return le.close()&&re.close()&&m.close()&&n.cut();}
}

public class headtest {
/**
* @param args
*/
public static void main(String[] args) {
// TODO Auto-generated method stub
head head1=new head(1,2,3,4,5,6);
System.out.println("The head's all of number is:"+head1);
}
}

理论上的输出应该是：The head's all of number is:123456
实际上输出是：The head's all of number is:head@120bf2c
请问这是为什么？哪里出了问题？

如果要改的话应该怎么改？

[解决办法]
head必须实现toString方法
public String toString()
{
return "" + r + w + h + x + y + z;
}
[解决办法]

Java code

class eye {    private int r;    public double pi() {        return 3.1416;    }    public eye(int r1) {        r = r1;    }    public int getR() {        return r;    }    public void setR(int r1) {        r = r1;    }    public boolean issmall() {        return r > 10;    }    public boolean close() {        return r == 0;    }}class mouth {    private int w, h;    public double pi() {        return 3.1416;    }    public mouth(int w1, int h1) {        w = w1;        h = h1;    }    public int getW() {        return w;    }    public int getH() {        return h;    }    public void setW(int w1) {        w = w1;    }    public void setH(int h1) {        h = h1;    }    public boolean isbig() {        return w > 10 || h > 5;    }    public boolean close() {        return w == 0 || h == 0;    }}class nose {    private int x, y, z;    public nose(int x1, int y1, int z1) {        x = x1;        y = y1;        z = z1;    }    public int getX() {        return x;    }    public int getY() {        return y;    }    public int getZ() {        return z;    }    public void setX(int x1) {        x = x1;    }    public void setY(int y1) {        y = y1;    }    public void setZ(int z1) {        z = z1;    }    public boolean isbig() {        return x > 10 || y > 10 || z > 10;    }    public boolean cut() {        return x == 0 || y == 0 || z == 0;    }}class head {    private int r;    private int w, h;    private int x, y, z;    private int numHair;    private int k;    eye le;    eye re;    nose n;    mouth m;    public head(int r1, int w1, int h1, int x1, int y1, int z1) {        r = r1;        w = w1;        h = h1;        x = x1;        y = y1;        z = z1;    }    public head(int nu, int k1, eye le1, eye re1, nose n1, mouth m1) {        numHair = nu;        k = k1;        le = le1;        re = re1;        n = n1;        m = m1;    }    public int getNumHair() {        return numHair;    }    public int getK() {        return k;    }    public eye getle() {        return le;    }    public eye getre() {        return re;    }    public nose getN() {        return n;    }    public mouth getM() {        return m;    }    public void setle(eye le1) {        le = le1;    }    public void setre(eye re1) {        re = re1;    }    public void setn(nose n1) {        n = n1;    }    public void setm(mouth m1) {        m = m1;    }    public void setNumHair(int nu) {        numHair = nu;    }    public void setK(int k1) {        k = k1;    }    public boolean isnormal() {        return le.getR() == re.getR();    }    public boolean headache() {        return le.close() && re.close() && m.close() && n.cut();    }        public String toString() {        return new StringBuffer().append(r).append(w).append(h).append(x).append(y).append(z).toString();    }}public class headtest {    /**     * @param args     */    public static void main(String[] args) {        // TODO Auto-generated method stub        head head1 = new head(1, 2, 3, 4, 5, 6);        System.out.println("The head's all of number is:" + head1);    }} 
 
[解决办法]
Java code
在head类中加入 @Overridepublic String toString() {   return "head:[r=" + r + ",w="+ w + ",h="+ h + ",x="+ x + ",y="+ y+ ",z="+ z+ "]"   ;}
[解决办法]
这不是乱码 head类是继承Object类的
而这里是输出的Object类的toString()方法。

默认的toString()方法是
public String toString() {
return getClass().getName() + "@" + Integer.toHexString(hashCode());
}

所以要输出想要的内容，head类里要重写toString方法。