与void show(int a, char b, double c){}构成重载的有：
a) void show(int x, char y, double z){} //no
b) int show(int a, double c, char b){} //yes
c) void show(int a, double c, char b){} //yes
d) boolean show(int c, char b){} //yes
e) void show(double c){} //yes
f) double show(int x, char y, double z){} //no
g) void shows(){double c} //no
形参个数可变
public static void test(int a ,String…books);
public static void test(int a ,String[] books);
其中形参中可变参数部分放在方法形参传入的最后
JAVA类的四种访问权限
