瞭解Java中的檢查與未檢查異常 - Understanding checked vs unchecked exceptions in Java

問題：

Joshua Bloch in " Effective Java " said that 約書亞·布洛赫（Joshua Bloch）在《 有效的Java 》中說

Use checked exceptions for recoverable conditions and runtime exceptions for programming errors (Item 58 in 2nd edition) 將檢查的異經常使用於可恢復的條件，將運行時異經常使用於編程錯誤（第二版中的項目58）

Let's see if I understand this correctly. 讓咱們看看我是否正確理解了這一點。

Here is my understanding of a checked exception: 這是我對檢查異常的理解：

try{
    String userInput = //read in user input
    Long id = Long.parseLong(userInput);
}catch(NumberFormatException e){
    id = 0; //recover the situation by setting the id to 0
}

1. Is the above considered a checked exception? 1.以上是否被視爲通過檢查的異常？

2. Is RuntimeException an unchecked exception? 2. RuntimeException是未經檢查的異常嗎？

Here is my understanding of an unchecked exception: 這是我對未經檢查的異常的理解：

try{
    File file = new File("my/file/path");
    FileInputStream fis = new FileInputStream(file);   
}catch(FileNotFoundException e){

//3. What should I do here?
    //Should I "throw new FileNotFoundException("File not found");"?
    //Should I log?
    //Or should I System.exit(0);?
}

4. Now, couldn't the above code also be a checked exception? 4.如今，上面的代碼難道不是一個檢查異常嗎？ I can try to recover the situation like this? 我能夠嘗試恢復這種狀況嗎？ Can I? 我能夠嗎？ (Note: my 3rd question is inside the catch above) （注：個人第三個問題是，裏面catch上）

try{
    String filePath = //read in from user input file path
    File file = new File(filePath);
    FileInputStream fis = new FileInputStream(file);   
}catch(FileNotFoundException e){
    //Kindly prompt the user an error message
    //Somehow ask the user to re-enter the file path.
}

5. Why do people do this? 5.人們爲何這樣作？

public void someMethod throws Exception{

}

Why do they let the exception bubble up? 爲何他們讓異常冒出來？ Isn't handling the error sooner better? 處理錯誤不是更好嗎？ Why bubble up? 爲何冒泡？

6. Should I bubble up the exact exception or mask it using Exception? 6.我應該冒充確切的異常仍是使用Exception屏蔽它？

Below are my readings 如下是個人讀物

In Java, when should I create a checked exception, and when should it be a runtime exception? 在Java中，何時應該建立一個檢查異常，何時應該是運行時異常？

When to choose checked and unchecked exceptions 什麼時候選擇已檢查和未檢查的異常

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解決方案：

參考一： https://stackoom.com/question/Pf1U/瞭解Java中的檢查與未檢查異常
參考二： https://oldbug.net/q/Pf1U/Understanding-checked-vs-unchecked-exceptions-in-Java