Java Exceptions: exception myException is never thrown in body of corresponding try statement

java exception try-catch throws
aitee picture aitee · Nov 30, 2010 · Viewed 11.3k times · Source

I understand the idea of this error. But I guess I don't understand how this works down the call stack.

File Main.java:

public static void main(String[] args) {
    try {
         Function1();
      } catch (myException e) {
      System.out.println(e.getMessage());
    }
}
public static void Function1() {
    Function2();
}

Function2 exists in another file:

File2.java

public void Function2() throws myException {
     ....
}

So through several calls (down the call stack) I have Function2 which specifies the requirement "throws myException". How come the main function (where the error is being directed at) doesn't recognize that I throw myException down the line?

Any guidance in where the 'hole' in my "exception knowledge" lies would be greatly appreciated.

aitee,

Answer

Carl Smotricz picture Carl Smotricz · Nov 30, 2010

The hole is that Function2 declares that it throws the exception, but Function1 does not. Java doesn't dig its way through possible call hierarchies, but goes directly by what you declare in throws statements.

Function1 gets away with not declaring the throw probably because myException is a RuntimeException.

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