[java] throw an exception

Exception handling is the basis of java, but since it was misrecognized, it is left as a memorandum.

Problems that occurred

I wanted to throw an exception to the method caller, so when I tried to throw the caught exception, I got a compile error for some reason.


For example, when throwing a timeout error, it is as follows.

    public void foo(){
        try {
        } catch (SocketTimeoutException e) {

    public Integer fetch(){
        try {
        } catch (SocketTimeoutException e) {
 throw e; // compile error here
        }finally {
        return number;


Besides throw There is a thorws clause, but I thought it had the same function as the catch statement. But in fact the method with it meant ** a method that could throw an exception **.

So I added a throws clause to the method throwing the exception and the compile error disappeared and I could catch it with foo ().


I didn't think I would stumble on the foundation of the foundation, but I'm glad I knew it now ...

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