Javaの例外処理で知らないと損する7つのテクニック

package sample24;
public class SampleException extends Exception {
    private static final long serialVersionUID = 1L;
    private int code;
    public SampleException(int code, String message) {
        super(message);
        this.code = code;
    }
    public int getCode() {
        return code;
    }
}

package sample24;
public class SampleException2 extends Exception {
    private static final long serialVersionUID = 1L;
    public SampleException2(String message) {
        super(message);
    }
}

package sample24;
public class SampleUserList {
    class UserInfo {
        private String name;
        private String password;
        public UserInfo(String name, String password) {
            this.name = name;
            this.password = password;
        }
        public String getName() { return name; }
        public String getPassword() { return password; }
    }
    private java.util.List users = 
        new java.util.ArrayList();
  
    public SampleUserList() {
        users.add(new UserInfo("Akira", "777"));
        users.add(new UserInfo("Jacky", "*"));
    }
  
    public boolean login(String name, String password)
    throws SampleException, SampleException2 {
        for (UserInfo user : users) {
            if ("".equals(name.trim())) {
                throw new SampleException(1, "ログインに失敗しました。");
            } else if ("".equals(password.trim())) {
                throw new SampleException(2, "ログインに失敗しました。");
            }
            if (user.getName().equals(name)) {
                if (user.getPassword().equals("*")) {
                    throw new SampleException2("ログインに失敗しました。");
                } else if (user.getPassword().equals(password)) {
                    return true;
                } else {
                    return false;
                }
            }
        }
        return false;
    }
}

package sample24;
public class SampleApp {
    public static void main(String[] args) {
        String[] users = { "Sara", "Akira", "Akira", "Jacky", "" };
        String[] passwords = { "", "777", "111", "abc", "xyz" };
        SampleUserList sample = new SampleUserList();
        for (int i = 0; i < users.length; i++) {
            try {
                System.err.print("i=" + i + ":");
                boolean isLogin = sample.login(users[i], passwords[i]);
                if (isLogin) {
                    System.err.println("ログインに成功しました。(" + users[i] + ")");
                } else {
                    System.err.println("ログインに失敗しました。");
                }
            } catch (SampleException e1) {
                e1.printStackTrace();
                System.err.println("code[" + e1.getCode() + "]");
            } catch (SampleException2 e2) {
                e2.printStackTrace();
            }
            System.err.println("");
        }
    }
}