Click here to watch in Youtube :
https://www.youtube.com/watch?v=osGHEAmqD2g&list=UUhwKlOVR041tngjerWxVccw
Student.java
public class Student { private String first; // first name private String last; // last name private String email; // email address private int section; // section number // construct a new student with given fields public Student(String first, String last, String email, int section) { this.first = first; this.last = last; this.email = email; this.section = section; } public void showStudentFullName() { System.out.println(first+last); } // return a string representation of the invoking object public String toString() { return section + " " + first + " " + last + " " + email; } }ReflectionDemo.java
import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.lang.reflect.Constructor; import java.lang.reflect.Field; import java.lang.reflect.Method; /** * How to display the metadata of a class. * */ public class ReflectionDemo { public static void main(String[] args) { try { BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); System.out.print("Enter the ClassName: "); String className= br.readLine(); br.close(); Class<?> classObj = Class.forName(className); System.out.println("Fields: "); /* * Returns:the array of Field objects representing all the declared * fields of this class */ Field[] fieldArray = classObj.getDeclaredFields(); for (Field field : fieldArray) { System.out.println(field); } System.out.println("---------------------------------------"); System.out.println("\nConstructors:"); /* * Returns:the array of Constructor objects representing all the * declared constructors of this class */ Constructor<?>[] constructorArray = classObj.getDeclaredConstructors(); for (Constructor<?> constructor : constructorArray) { System.out.println(constructor); } System.out.println("---------------------------------------"); System.out.println("\nMethods:"); /* * Returns:the array of Method objects representing all the declared * methods of this class */ Method[] methodArray = classObj.getDeclaredMethods(); for (Method method : methodArray) { System.out.println(method); } } catch (ClassNotFoundException | IOException e) { e.printStackTrace(); } } }Output
Enter the ClassName: java.util.ArrayList Fields: private static final long java.util.ArrayList.serialVersionUID private static final int java.util.ArrayList.DEFAULT_CAPACITY private static final java.lang.Object[] java.util.ArrayList.EMPTY_ELEMENTDATA private static final java.lang.Object[] java.util.ArrayList.DEFAULTCAPACITY_EMPTY_ELEMENTDATA transient java.lang.Object[] java.util.ArrayList.elementData private int java.util.ArrayList.size private static final int java.util.ArrayList.MAX_ARRAY_SIZE --------------------------------------- Constructors: public java.util.ArrayList(java.util.Collection) public java.util.ArrayList() public java.util.ArrayList(int) --------------------------------------- Methods: public boolean java.util.ArrayList.add(java.lang.Object) public void java.util.ArrayList.add(int,java.lang.Object) public boolean java.util.ArrayList.remove(java.lang.Object) public java.lang.Object java.util.ArrayList.remove(int) public java.lang.Object java.util.ArrayList.get(int) public java.lang.Object java.util.ArrayList.clone() public int java.util.ArrayList.indexOf(java.lang.Object) public void java.util.ArrayList.clear() public boolean java.util.ArrayList.contains(java.lang.Object) public boolean java.util.ArrayList.isEmpty() public java.util.Iterator java.util.ArrayList.iterator() public int java.util.ArrayList.lastIndexOf(java.lang.Object) public void java.util.ArrayList.replaceAll(java.util.function.UnaryOperator) public int java.util.ArrayList.size() public java.util.List java.util.ArrayList.subList(int,int) public java.lang.Object[] java.util.ArrayList.toArray(java.lang.Object[]) public java.lang.Object[] java.util.ArrayList.toArray() public java.util.Spliterator java.util.ArrayList.spliterator() static int java.util.ArrayList.access$100(java.util.ArrayList) public boolean java.util.ArrayList.addAll(int,java.util.Collection) public boolean java.util.ArrayList.addAll(java.util.Collection) private void java.util.ArrayList.readObject(java.io.ObjectInputStream) throws java.io.IOException,java.lang.ClassNotFoundException private void java.util.ArrayList.writeObject(java.io.ObjectOutputStream) throws java.io.IOException public void java.util.ArrayList.forEach(java.util.function.Consumer) public java.lang.Object java.util.ArrayList.set(int,java.lang.Object) public void java.util.ArrayList.ensureCapacity(int) public void java.util.ArrayList.trimToSize() private void java.util.ArrayList.ensureCapacityInternal(int) private static int java.util.ArrayList.hugeCapacity(int) java.lang.Object java.util.ArrayList.elementData(int) private void java.util.ArrayList.grow(int) public java.util.ListIterator java.util.ArrayList.listIterator() public java.util.ListIterator java.util.ArrayList.listIterator(int) public boolean java.util.ArrayList.removeAll(java.util.Collection) public boolean java.util.ArrayList.removeIf(java.util.function.Predicate) protected void java.util.ArrayList.removeRange(int,int) public boolean java.util.ArrayList.retainAll(java.util.Collection) public void java.util.ArrayList.sort(java.util.Comparator) private java.lang.String java.util.ArrayList.outOfBoundsMsg(int) private void java.util.ArrayList.rangeCheckForAdd(int) private boolean java.util.ArrayList.batchRemove(java.util.Collection,boolean) private void java.util.ArrayList.ensureExplicitCapacity(int) private void java.util.ArrayList.fastRemove(int) private void java.util.ArrayList.rangeCheck(int) static void java.util.ArrayList.subListRangeCheck(int,int,int)Click the below link to download the code:
https://sites.google.com/site/ramj2eev1/home/javabasics/ReflectionDemo_display_metadata.zip?attredirects=0&d=1
Github Link:
https://github.com/ramram43210/Java/tree/master/BasicJava/ReflectionDemo_display_metadata
Bitbucket Link:
https://bitbucket.org/ramram43210/java/src/6c95796df09abfb09587d07613e2e6d5f9ad024e/BasicJava/ReflectionDemo_display_metadata/?at=master
See also:
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