An exception in a throws declaration in Java is redundant if:

• It is listed multiple times
• It is a subclass of another listed exception
• It is a RuntimeException, or one of its descendants

The following code:

void foo() throws MyException, MyException {}  // Non-Compliant - should be listed once
void bar() throws Throwable, Exception {}      // Non-Compliant - Exception is a subclass of Throwable
void baz() throws RuntimeException {}          // Non-Compliant - RuntimeException can always be thrown

should be refactored into:

void foo() throws MyException {}               // Compliant
void bar() throws Throwable {}                 // Compliant
void baz() {}                                  // Compliant