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POInstantiating abstract classes in Java: Why does this work?
 

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  1. POInstantiating abstract classes in Java: Why does this work?
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    <blockquote> <p><strong>Possible Duplicate:</strong><br> <a href="https://stackoverflow.com/questions/13670991/interview-can-we-instantiate-abstract-class">Interview : Can we instantiate abstract class?</a> </p> </blockquote> <p>I have an abstract class with all its methods defined (i.e. there are no abstract methods contained within it) like the following: </p> <pre class="lang-java prettyprint-override"><code>public abstract class MyAbstractClass { String s; public void setString(String s) { this.s = s; } public String getString() { return this.s; } } </code></pre> <p>There is also a JUnit test class:</p> <pre class="lang-java prettyprint-override"><code>public class TestClass { MyAbstractClass c; @Before public void setUp() { // What is happening here? And why does this work with an abstract class? // Instantiation? Extending the abstract class? Overwriting? c = new MyAbstractClass() { }; // This will not work: (Why?) // c = new MyAbstractClass(); } @Test public void test_AllMethodsAvailable() { // Why can I access the abstract class' methods? // Shouldn't they be overwritten? Or did I extend the class? c.setString("Test"); assertEquals("Test", c.getString()); } } </code></pre> <p>I don't quite understand why the assignment to <code>c</code> works in the first case but not in the second, or what is actually happening there (and as a consequence, why accessing the abstract class' methods works in the test). </p> <p>Can somebody please explain (and possibly point me to a Javadoc, article or book that explains why this works)? </p> <p>Why can I "instantiate" an abstract class there? (Is that actually what I'm doing?) </p> <p>Has it to do with inner classes?</p>
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