Question

public class MyClass {
  public static void method() {
    try {
    // there is no compile time error for unnecessary catching 'Exception'
    } catch (Exception e) {
      e.printStackTrace();
    }
  }

  public static void main(String[] args) {
    try {
      // why compile time error for unnecessary catching 'MyException' or
      // 'CloneNotSupportedException' etc..
      // ultimately Exception, MyException &  CloneNotSupportedException all 
      // are checked exception
      

    } catch (MyException e) {
      e.printStackTrace();
    }
  }
}
class MyException extends Exception {
}

second scenario
---------------
public class MyClass {
    public static void method() throws Exception {
    }

    public static void main(String[] args) {
        // if Exception itself is not checked ,
        // why compile time error occured for calling method(); ??
        method();
    }
}

Answer 1

Because RuntimeExceptions are subclasses of Exception class. Therefore, compiler can’t determine if some code throws any runtime exception, as they might be thrown by jvm.
On the other hand – checked exceptions must be declared that are thrown by some method, so the compiler knows which exceptions could be thrown and can determine unnecessary catch blocks.