Here we are going to write a program, how to get the Constructor Information using Java Reflection mechanism.
Get Constructor Information :
[java]
package com.onlinetutorialspoint.ref;
public class Reflection_Constructor_Info {
public static void main(String[] args) {
if (args.length == 0) {
System.out.println("PLEASE PASS THE CLASS NAME..!");
} else {
try {
Class c = Class.forName(args[0]);
printConsts(c);
} catch (ClassNotFoundException cnfe) {
System.out.println(args[0] + " DOES NOT EXISTS…");
}
}
}
static void printConsts(Class c) {
java.lang.reflect.Constructor Cons[] = c.getConstructors();
System.out.println("NUMBER OF CONSTRUCTORS = " + Cons.length);
System.out.println("NAME OF THE CONSTRUCTOR : " + c.getName());
for (int i = 0; i < Cons.length; i++) {
System.out.print(c.getName() + "(");
Class cp[] = Cons[i].getParameterTypes();
for (int j = 0; j < cp.length; j++) {
System.out.print(cp[j].getName() + ")");
}
System.out.println("\b" + ")");
}
}
}
[/java]
Output :
javac Reflection_Constructor_Info.java java Reflection_Constructor_Info java.awt.TextArea NUMBER OF CONSTRUCTORS = 5 NAME OF THE CONSTRUCTOR : java.awt.TextArea java.awt.TextArea(java.lang.String)int)int) java.awt.TextArea(java.lang.String)int)int)int) java.awt.TextArea) java.awt.TextArea(java.lang.String) java.awt.TextArea(int)int)
Happy Learning 🙂
