JAVA charAt

■Test05.java

public class Test05 {
    public static void main(String[] args) {
        System.out.println(Test05("zzz11111"));
        System.out.println(Test05("ZAZ11111"));
        Boolean v = Test05("BBB0687S");
        System.out.println(Test05("AAAAAAAA"));
        System.out.println(v);
    }

    static boolean Test05(String name) {
        if (name.length() != 8) {
            // String x = "エラー";
            // System.out.println(x);
            return false;
        }
        char first = name.charAt(0);
        if (!(first >= 'A' && first <= 'Z')) {
            return false;
        }
        for (int i = 1; i < 8; i++) {
            char c = name.charAt(i);
            if (!((c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9'))) {
                return false;
            }
        }
        return true;

    }

}

■Test05.java 実行結果
false
true
true
true