java: switch的特点

package com.chnfuture;

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.NoSuchAlgorithmException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;

public class Test {
    public static void main(String[] args) {
        char c = 'a';
        switch (c) {
        default:
            System.out.println("default!");
        case 'b':
            System.out.println("b");
            
        case 'c':
            System.out.println("c");
            break;
        case 'd':
            System.out.println("d");
            break;
        case 'e':
            System.out.println("e");
            break;
        
        }
    }
}