- Given a class in java containing public,private & protected contructors.
- Get/list/print all constructors (prive,protected & public) of a class using Class.
- getConstructors method of Class will list all public constructors of given class.
- getDeclaredConstructors method of Class will list all private, protected & public constructors
| No. | Method Name |
Description |
|---|
| 1 | Constructor<?>[] getConstructors() |
Returns an array containing Constructor objects reflecting all the public constructors of the class represented by this Class object. |
| 2 | Constructor<?>[] getDeclaredConstructors() |
Returns an array of Constructor objects reflecting all the constructors declared by the class represented by this Class object. |
1. Print/list public/protected/private constructors of class in java (example)
package org.learn.classes;
import java.lang.reflect.Constructor;
import java.util.Date;
class Vehicle {
private String owner;
private float cost;
private String model;
private Vehicle() {
}
protected Vehicle(String owner, float cost) {
this.owner = owner;
this.cost = cost;
}
public Vehicle(String owner, float cost, String model) {
this.owner = owner;
this.cost = cost;
this.model = model;
}
}
public class DemoGetClassConstructors {
public static void main(String[] args) {
final Constructor<?>[] allConstructors = Vehicle.class.getConstructors();
System.out.println("1. Get public constructors of Vehicle class");
for (Constructor constructor : allConstructors) {
System.out.println(constructor);
}
System.out.println("2. End - public constructors of Vehicle class");
System.out.println();
System.out.println("3. Get all declared (private,protected,public) constructors of Vehicle class");
final Constructor<?>[] declaredConstructors = Vehicle.class.getDeclaredConstructors();
for (Constructor constructor : declaredConstructors) {
System.out.println(constructor);
}
System.out.println("4. End - all declared constructors of Vehicle class");
}
}
2. Output: public/protected/private constructors of class in java (example)
1. Get public constructors of Vehicle class
public org.learn.classes.Vehicle(java.lang.String,float,java.lang.String)
2. End get public constructors of Vehicle class
3. Get all declared (private,protected,public) constructors of Vehicle class
private org.learn.classes.Vehicle()
protected org.learn.classes.Vehicle(java.lang.String,float)
public org.learn.classes.Vehicle(java.lang.String,float,java.lang.String)
4. End Get all declared constructors of Vehicle class
