Difference betwixt NoClassDefFoundError vs ClassNotFoundExcepiton inwards Java

Both NoClassDefFoundError as well as ClassNotFoundException are unsafe errors which come upwardly when JVM or ClassLoader non able to locate bird during the class loading process. Since dissimilar ClassLoader loads classes from a dissimilar location, sometimes this number may live caused because of wrong CLASSPATH equally good i.e. about JAR files from lib are missing or from the onetime version. Though hold off quite like in that place is a subtle difference betwixt NoClassDefFoundError as well as ClassNotFoundException, NoClassDefFoundError indicates that bird was introduce during the fourth dimension of compilation simply non available when yous run Java program, sometimes fault on static initializer block tin equally good effect inwards NoClassDefFoundError.

On the other hand, ClassNotFoundException is naught to create amongst compile time, ClassNotFoundException comes when yous endeavor to charge a bird inwards runtime using Reflection, e.g. loading SQL drivers as well as corresponding Classloader is non able to honour this class. Apart from this key deviation betwixt NoClassDefFoundError as well as ClassNoFoundException inwards Java, let's meet about to a greater extent than points for ameliorate understanding.

NoClassDefFoundError vs ClassNotFoundException

In short, both ClassNotFoundException and NoClassDefFoundError are caused yesteryear missing classes inwards CLASSPATH, normally due to missing JAR files, simply if JVM initiates the procedure due to transitive reference as well as failed to charge the bird at runtime it throws java.lang.NoClassDefFoundError, field if your code explicitly tries to charge the classes e.g. yesteryear using Class.forName() method as well as bird is non introduce inwards CLASSPATH, thence JVM throws java.lang.ClassNotFoundException.

You volition ofttimes honour a NoClassDefFoundError truly caused yesteryear ClassNotFoundException, yous tin meet it yesteryear looking for "Caused By: " give-and-take inwards the fault message.

Let's meet about to a greater extent than differences betwixt both of them inwards dot form:

1) NoClassDefFoundError is an Error which is unchecked inwards nature, i.e. doesn't take away try-catch or locomote block. On the other hand, ClassNotFoundException is a checked Exception as well as requires mandatory treatment using either endeavor amongst select grip of block or endeavor amongst the finally block, failure to create thence volition effect inwards compile fourth dimension error.

2) If yous are experiencing NoClassDefFoundError inwards the J2EE environment, in that place could live the host of reason, i beingness multiple bird loader as well as visibility of bird amidst them. See 3 ways to solve NoClassDefFoundError for to a greater extent than details.

3) Often java.lang.ClassNotFoundException is thrown equally effect of next method call, Class.forName(), ClassLoader.findSystemClass() as well as ClassLoader.loadClass().

4) Another deviation betwixt NoClassDefFoundError as well as ClassNotFoundException is that NoClassDefFoundError is a LinkageError as well as tin come upwardly during linking, field java.lang.ClassNotFoundException is an Exception as well as occurs during runtime.

Here is a dainty slide of all the differences betwixt java.lang.NoClassDefFoundError as well as java.lang.ClassNotFoundException inwards Java:

are unsafe errors which come upwardly when JVM or Difference betwixt NoClassDefFoundError vs ClassNotFoundExcepiton inwards Java

That's all on the difference betwixt NoClassDefFoundError vs ClassNotFoundException inwards Java. Just cry upwardly these listing of deviation field debugging or troubleshooting NoClassDefFoundError or ClassNotFoundException, this volition trim confusion as well as help to solve the employment quickly.

Other Java Interview questions explanation from

Difference betwixt TreeSet as well as TreeMap inwards Java

Difference betwixt Hashtable as well as HashMap inwards Java

Difference betwixt ArrayList vs Vector inwards Java

Difference betwixt ConcurrentHashMap as well as HashMap inwards Java

Difference betwixt StringBuffer as well as String inwards Java

Further Reading
Java Puzzlers yesteryear Joshua Bloch
Java Performance The Definitive Guide