In this example we shall show you how the class loader works. To see how the class loader works we have performed the following steps:
- We have created three classes,
A,BandC, that each one uses a static block to print a message. The code in a static block is executed when the class is loaded by the class loader. - We create a new instance of
Aclass, then we get an object ofBclass, using theforName(String className)API method of Class and then we create a newCobject and see the printed messages from the static blocks,
as described in the code snippet below.
package com.javacodegeeks.snippets.core;
class A {
static {
System.out.println("Loading A");
}
}
class B {
static {
System.out.println("Loading B");
}
}
class C {
static {
System.out.println("Loading C");
}
}
public class ClassLoader {
public static void main(String[] args) {
System.out.println("inside main");
new A();
System.out.println("inside main : After creating A");
try {
Class.forName("B");
} catch (ClassNotFoundException e) {
System.out.println("inside main : Couldn't find B");
}
System.out.println("inside main : After Class.forName("B")");
new C();
System.out.println("inside main : After creating C");
}
}
Output:
inside main
Loading A
inside main : After creating A
inside main : Couldn't find B
inside main : After Class.forName("B")
Loading C
inside main : After creating C
This was an example of how the class loader works in Java.
