Java lang classnotfoundexception with

but no definition for the class with the specified name could be found.

As of release 1.4, this exception has been retrofitted to conform to the general purpose exception-chaining mechanism. The «optional exception that was raised while loading the class» that may be provided at construction time and accessed via the getException() method is now known as the cause, and may be accessed via the Throwable.getCause() method, as well as the aforementioned «legacy method.»

Constructor Summary

Constructs a ClassNotFoundException with the specified detail message and optional exception that was raised while loading the class.

Method Summary

Returns the cause of this exception (the exception that was raised if an error occurred while attempting to load the class; otherwise null ).

Methods declared in class java.lang.Throwable

Methods declared in class java.lang.Object

Constructor Detail

ClassNotFoundException

public ClassNotFoundException()

ClassNotFoundException

Constructs a ClassNotFoundException with the specified detail message and optional exception that was raised while loading the class.

Method Detail

getException

Returns the exception that was raised if an error occurred while attempting to load the class. Otherwise, returns null . This method predates the general-purpose exception chaining facility. The Throwable.getCause() method is now the preferred means of obtaining this information.

getCause

Returns the cause of this exception (the exception that was raised if an error occurred while attempting to load the class; otherwise null ).

Report a bug or suggest an enhancement
For further API reference and developer documentation see the Java SE Documentation, which contains more detailed, developer-targeted descriptions with conceptual overviews, definitions of terms, workarounds, and working code examples.
Java is a trademark or registered trademark of Oracle and/or its affiliates in the US and other countries.
Copyright © 1993, 2023, Oracle and/or its affiliates, 500 Oracle Parkway, Redwood Shores, CA 94065 USA.
All rights reserved. Use is subject to license terms and the documentation redistribution policy.

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Class ClassNotFoundException

but no definition for the class with the specified name could be found.

Constructor Summary

Constructs a ClassNotFoundException with the specified detail message and optional exception that was raised while loading the class.

Method Summary

Methods declared in class java.lang.Throwable

Methods declared in class java.lang.Object

Constructor Details

ClassNotFoundException

Constructs a ClassNotFoundException with the specified detail message and optional exception that was raised while loading the class.

Method Details

getException

Returns the exception that was raised if an error occurred while attempting to load the class. Otherwise, returns null .

Report a bug or suggest an enhancement
For further API reference and developer documentation see the Java SE Documentation, which contains more detailed, developer-targeted descriptions with conceptual overviews, definitions of terms, workarounds, and working code examples. Other versions.
Java is a trademark or registered trademark of Oracle and/or its affiliates in the US and other countries.
Copyright © 1993, 2023, Oracle and/or its affiliates, 500 Oracle Parkway, Redwood Shores, CA 94065 USA.
All rights reserved. Use is subject to license terms and the documentation redistribution policy.

Источник

Class ClassNotFoundException

but no definition for the class with the specified name could be found.

Constructor Summary

Constructs a ClassNotFoundException with the specified detail message and optional exception that was raised while loading the class.

Method Summary

Methods declared in class java.lang.Throwable

Methods declared in class java.lang.Object

Constructor Details

ClassNotFoundException

Constructs a ClassNotFoundException with the specified detail message and optional exception that was raised while loading the class.

Method Details

getException

Returns the exception that was raised if an error occurred while attempting to load the class. Otherwise, returns null .

Report a bug or suggest an enhancement
For further API reference and developer documentation see the Java SE Documentation, which contains more detailed, developer-targeted descriptions with conceptual overviews, definitions of terms, workarounds, and working code examples. Other versions.
Java is a trademark or registered trademark of Oracle and/or its affiliates in the US and other countries.
Copyright © 1993, 2023, Oracle and/or its affiliates, 500 Oracle Parkway, Redwood Shores, CA 94065 USA.
All rights reserved. Use is subject to license terms and the documentation redistribution policy.

Источник

Java lang classnotfoundexception with

Constructs a ClassNotFoundException with the specified detail message and optional exception that was raised while loading the class.

Method Summary

Returns the cause of this exception (the exception that was raised if an error occurred while attempting to load the class; otherwise null).

Methods inherited from class java.lang.Throwable

Methods inherited from class java.lang.Object

Constructor Detail

ClassNotFoundException

public ClassNotFoundException()

ClassNotFoundException

Constructs a ClassNotFoundException with the specified detail message and optional exception that was raised while loading the class.

Method Detail

getException

Returns the exception that was raised if an error occurred while attempting to load the class. Otherwise, returns null. This method predates the general-purpose exception chaining facility. The Throwable.getCause() method is now the preferred means of obtaining this information.

getCause

Returns the cause of this exception (the exception that was raised if an error occurred while attempting to load the class; otherwise null).

Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
Copyright © 1993, 2023, Oracle and/or its affiliates. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.

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Java ClassNotFoundException — java.lang.ClassNotFoundException

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Java ClassNotFoundException

Java ClassNotFoundException occurs when the application tries to load a class but Classloader is not able to find it in the classpath.
Common causes of java.lang.ClassNotFoundException are using Class.forName or ClassLoader.loadClass to load a class by passing String name of a class and it’s not found on the classpath.
ClassNotFoundException is a checked exception, so it has to be catch or thrown to the caller.
ClassNotFoundException always occurs at runtime because we are indirectly loading the class using Classloader. Java compiler has no way to know if the class will be present in the classpath at runtime or not.
One of the most common example of ClassNotFoundException is when we try to load JDBC drivers using Class.forName but forget to add it’s jar file in the classpath.

Java ClassNotFoundException Example

Let’s look at a simple example where we will get ClassNotFoundException .

package com.journaldev.exceptions; public class DataTest < public static void main(String[] args) < try < Class.forName("com.journaldev.MyInvisibleClass"); ClassLoader.getSystemClassLoader().loadClass("com.journaldev.MyInvisibleClass"); ClassLoader.getPlatformClassLoader().loadClass("com.journaldev.MyInvisibleClass"); >catch (ClassNotFoundException e) < e.printStackTrace(); >> >

Note that com.journaldev.MyInvisibleClass doesn’t exist, so When we execute above program, we get following exception stack trace.

java.lang.ClassNotFoundException: com.journaldev.MyInvisibleClass at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:582) at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:185) at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:496) at java.base/java.lang.Class.forName0(Native Method) at java.base/java.lang.Class.forName(Class.java:292) at com.journaldev.exceptions.DataTest.main(DataTest.java:7)

In above example, all the three statements will throw java.lang.ClassNotFoundException .

How to resolve ClassNotFoundException

It’s very easy to fix ClassNotFoundException because the exception stack trace clearly specifies the class not found. Just check for classpath settings and make sure class it’s present at runtime.

ClassNotFoundException vs NoClassDefFoundError

NoClassDefFoundError is a runtime error thrown when a class is not found at runtime. It’s very similar to ClassNotFoundException . Read more at Java NoClassDefFoundError. Reference: API Doc

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