Is Exception checked or not in JAVA?

Question

Consider the following code

public void myMethod1() {
    try {
        this.getClass().getMethod("myMethod").invoke(this);
    } catch (Exception e) {
        throw e;
    }
}

public void myMethod1_fixed() throws Exception {
    try {
        this.getClass().getMethod("myMethod").invoke(this);
    } catch (Exception e) {
        throw e;
    }
}

public void myMethod2() {
    try {
        this.getClass().getMethod("myMethod").invoke(this);
    } catch (IllegalAccessException | InvocationTargetException | NoSuchMethodException e) {
    } catch (Exception e) {
        throw e;
    }
}

myMethod1() was complaining about not handling the Exception e being thrown, which I understand because Exception is checked exception and you are forced to handle it, hence the myMethod1_fixed() added throws Exception and it was happy.

Now with myMethod2() it also throws Exception e, but it was happy even though there was no throws Exception, meaning Exception is unchecked?

Answer 1

As explained in Rethrowing Exceptions with More Inclusive Type Checking, the compiler considers which actual exception may occur, when you catch and re-throw exceptions, since Java 7.

So in

try {
    this.getClass().getMethod("myMethod").invoke(this);
} catch (IllegalAccessException | InvocationTargetException | NoSuchMethodException e) {
} catch (Exception e) {
    throw e;
}

you already catched all checked exception in the previous catch clause, and only unchecked exception are possible.

Note that you must not modify the variable e for this to work.