Created
May 31, 2017 19:03
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Playing with reflection.
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import java.io.IOException; | |
import java.lang.reflect.*; | |
/** | |
* Created by melisa on 31/05/2017. | |
*/ | |
class Person { | |
private String privateName; | |
public String publicName; | |
public Person friend; | |
public Person(String privateName , String publicName) | |
{ | |
this.privateName = privateName; | |
this.publicName = publicName; | |
} | |
public void beFriend(Person friend) | |
{ | |
this.friend = friend; | |
} | |
private void unfriend() | |
{ | |
if(friend!=null) | |
friend = null; | |
} | |
public void exceptional() throws Exception | |
{ | |
throw new IOException(); | |
} | |
public String toString() | |
{ | |
return new String(publicName + privateName); | |
} | |
} | |
public class PersonTest | |
{ | |
public static void main(String [] args) | |
{ | |
Class c1 = Person.class; | |
System.out.println("Class :" + c1); | |
System.out.println("Class Name :" + c1.getName()); | |
System.out.println("Class Type :" + c1.getTypeName()); | |
System.out.println("Super Class :" + c1.getSuperclass()); | |
Method [] methods = c1.getMethods(); | |
System.out.println("GetMethods"); | |
for(Method m : methods) | |
{ System.out.println(m); | |
System.out.println(m.getName()); | |
System.out.println(m.getModifiers()); | |
System.out.println(m.getDeclaringClass()); | |
System.out.println("----"); | |
} | |
System.out.println(); | |
Method [] declaredMethods = c1.getDeclaredMethods(); | |
System.out.println("GetDeclaredMethods"); | |
for(Method m : declaredMethods) | |
{ System.out.println(m); | |
System.out.println(m.getName()); | |
System.out.println(m.getModifiers()); | |
System.out.println(m.getDeclaringClass()); | |
System.out.println("----"); | |
} | |
System.out.println(); | |
Field [] fields = c1.getFields(); | |
System.out.println("GetFields"); | |
for(Field m : fields) | |
{ System.out.println(m); | |
System.out.println(m.getModifiers()); | |
System.out.println(m.getType()); | |
} | |
System.out.println(); | |
Field [] declaredFields = c1.getDeclaredFields(); | |
System.out.println("GetDeclaredFields"); | |
for(Field m : declaredFields) | |
System.out.println(m); | |
System.out.println(); | |
Person[] personList = new Person[2]; | |
personList[0] = new Person("Christ", "Jesus"); | |
personList[1] = new Person("St.", "Joseph"); | |
for(Person p : personList) | |
System.out.println(p); | |
System.out.println(); | |
Person[] personList2= (Person[]) Array.newInstance(c1,5); | |
personList2[0] = new Person("Bach", "Sebastian"); | |
personList2[1] = new Person("Mozart", "Amadeus"); | |
personList2[2] = new Person("Bethooven", "Ludwig Van"); | |
personList2[3] = new Person("Brahms", "Johannes"); | |
Array.set(personList2,4,new Person("Vivaldi","Antonio")); | |
for(Person p : personList2) | |
System.out.println(p); | |
System.out.println(); | |
Class[] paramTypes = new Class[]{String.class,String.class}; | |
try { | |
//Throws Exception If the constructor isn't public. | |
Constructor cons = c1.getConstructor(paramTypes); | |
Object[] arguments = new Object[] {"Myung", "John"}; | |
Person p = (Person) cons.newInstance(arguments); | |
System.out.println("Created Object With Reflection: " + p ); | |
Method m = p.getClass().getDeclaredMethod("exceptional"); | |
System.out.println(m.getName()); | |
m.invoke(p); | |
} catch (NoSuchMethodException | IllegalAccessException | InstantiationException e) { | |
e.printStackTrace(); | |
} | |
catch (InvocationTargetException e) | |
{ | |
System.out.println(e.getCause()); | |
} | |
} | |
} |
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