Javaは入力文字がa-zかA-Zか数字かを判断する

import java.util.Scanner; public class demo01 {

public static void main(String[] args) {
	// TODO Auto-generated method stub
	System.out.println("   ：");
	Scanner input = new Scanner(System.in);
	
	int a = input.next().charAt(0);
	
	if(a>0||a<0)
	{
		System.out.println("       ！");
	}else if(a>='A'&&a<='Z')
	{
		System.out.println("        ！");
	}else if(a>'a'&&a

}