Session6 module8 9 annotations reflection
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Module 8 – Annotations
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// Definition of an Annotation type
public @interface TestAnnotation {
String value;
}
// Usage of Annotation
@TestAnnotation (value="name")
public void display() {}
Uses of Annotations
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DO
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if the metadata changes the
design of the class.
if the metadata changes the
design of code dealing with
class.
if the metadata changes the
design of the class.
if the metadata changes the
design of code dealing with
class.
DON’T
DON’T
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@Deprecated static void deprecatedMethod() { }
}
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class Thu
{
@Deprecated
public void chao() {System.out.println("\n Hello");}
}
class ThuTest
{
@SuppressWarnings({"deprecation"})
public void test()
{ Thu t = new Thu();
t.chao();
}
}
public class SuppressWarning
{
public static void main(String[] args)
{
ThuTest h = new ThuTest();
h.test();
}
}
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@Retention(RetentionPolicy.SOURCE)
@interface Test_Retention
{
String v1();
}
class RetentionTest
{
@Test_Retention(v1="Hello")
public void thu() {System.out.println("Test annotations");}
}
class RetentionAnno
{public static void main(String args[])
{ new RetentionTest().thu();
}
}
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Module 9
Re2ection API
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