编写方法检验一个字符串是否是合法的密码

public static void main(String[] args){
{
Scanner input = new Scanner(System.in);
System.out.print("please input a code :");
String code = input.nextLine();
int count = 0;
boolean a=false;
boolean b=true;
boolean c=false;


if(code.length()>8)
a = true;
for(int i=0;i<code.length();i++){
char j = code.charAt(i);
if(j<='9'&&j>='0')
count++;
}
if(count>=2)
c = true;
for(int i=0;i<code.length();i++){
char j = code.charAt(i);
if((j<='a'||j>='z')&&(j<='A'||j>='Z')){
b = false;
System.out.println("the code is a "+(a&&b&&c)+" code");
System.exit(0);
}
}


System.out.println("the code is a "+(a&&b&&c)+" code");
}
}
}

哪错了？