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Thread: Why is answer A correct and not answer B?? I always thought a class has to implement an interface!! Is it different with generics?

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    Default Why is answer A correct and not answer B?? I always thought a class has to implement an interface!! Is it different with generics?

    QUESTION: 163
    A programmer must create a generic class MinMax and the type parameter of MinMax
    must implement Comparable. Which implementation of MinMax will compile?
    A. class MinMax<E extends Comparable<E>> {
    E min = null;
    E max = null;
    public MinMax() {}
    public void put(E value) { /* store min or max */ }
    B. class MinMax<E implements Comparable<E>> {
    E min = null;
    E max = null;
    public MinMax() {}
    public void put(E value) { /* store min or max */ }
    C. class MinMax<E extends Comparable<E>> {
    <E> E min = null;
    <E> E max = null;
    public MinMax() {}
    public <E> void put(E value) { /* store min or max */ }
    D. class MinMax<E implements Comparable<E>> {
    <E> E min = null;
    <E> E max = null;
    public MinMax() {}
    public <E> void put(E value) { /* store min or max */ }

    Correct Answer: A


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    Super Moderator curmudgeon's Avatar
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    Default Re: Why is answer A correct and not answer B?? I always thought a class has to implement an interface!! Is it different with generics?


  3. The Following User Says Thank You to curmudgeon For This Useful Post:

    TheCoder (March 9th, 2013)

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    Default Re: Why is answer A correct and not answer B?? I always thought a class has to implement an interface!! Is it different with generics?

    The link was fantastic advice. I found my answer. Many thanks

  5. #4
    Super Moderator curmudgeon's Avatar
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    Default Re: Why is answer A correct and not answer B?? I always thought a class has to implement an interface!! Is it different with generics?

    You're welcome.

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