Java: Check whether a class exists in the classpath or not

By loading the class, we can check whether the class exists in the class path or not. Below snippet checks whether a class is available in the class path or not.

 

 

Find the below working application.

 

ClassAvailableCheck.java

package com.sample.app.reflections;

public class ClassAvailableCheck {
	
	public static boolean isClassAvailable(String classQualifiedName) {
        ClassLoader classLoader = ClassAvailableCheck.class.getClassLoader();
        try {
            Class<?> laodedClazz = classLoader.loadClass(classQualifiedName);
            return (laodedClazz != null);
        } catch (ClassNotFoundException e) {
        	e.printStackTrace();
            return false;
        }
    }

	public static void main(String[] args) {
		System.out.println("is java.lang.System available: " + isClassAvailable("java.lang.System"));
		System.out.println("is org.json.JsonUtil available : " + isClassAvailable("org.json.JsonUtil"));
	}

}

Sample Output

is java.lang.System available: true
java.lang.ClassNotFoundException: org.json.JsonUtil
    at java.net.URLClassLoader.findClass(URLClassLoader.java:387)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
    at com.sample.app.reflections.ClassAvailableCheck.isClassAvailable(ClassAvailableCheck.java:8)
    at com.sample.app.reflections.ClassAvailableCheck.main(ClassAvailableCheck.java:18)
is org.json.JsonUtil available : false

 

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