Java : Check Your Understanding

Name:
  1. Equality
    In Java, what is the difference between the comparision operator, ==, and the comparision method, equals, when comparing objects?
  2. Object References
    Consider the following two innocent looking methods:
    3. StringBuffer getText ()
{
    return myText;
}


String getName ()
{
    return myName;
}

    Because every object variable in Java is a reference, explain why the first method has the potential to break the encapsulation of the object, while the second method does not.
  3. Swapping two values
    In C++, the following method swaps any two values passed: 
    4. template<class T>
void swap (T& a, T& b)
{
    T tmp = a;
    a = b;
    b = tmp;
}

    In Java, however, the following version of the method has no effect on the two values passed: 

    void swap (Object a, Object b)
{
    Object tmp = a;
    a = b;
    b = tmp;
}
    1. Even though all object variables in Java are actually references, explain why the Java version of swap does not work.
    2. Describe a way to write a generic swap method in Java. You do not need write your solution in Java code, just explain what is needed to make a swap method possible.
  4. What is the main difference between running programs in C++ and Java? What impact does that have in terms of compile-time versus run-time errors?
    5.