blocks|key|287479|text|如果您知道类或包含类的jar的路径，那么在运行它时将其添加到类路径中。您可以使用如下所述的类路径：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|287480|在Windows上|287481|java+-classpath+.;yourjar.jar+YourMainClass|code-block|syntax|javascript|287482|在UNIX/Linux上|287483|java+-classpath+.:yourjar.jar+YourMainClass|287484|entityMap^0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|P|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Q|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|R|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|M|3|-4|5|6|7|T|8|@]|9|@]|A|$]]]|N|$]]

If you know the path of the class or the jar containing the class then add it to your classpath while running it. You can use the classpath as mentioned here:

on Windows

<pre><code>java -classpath .;yourjar.jar YourMainClass
</code></pre>

on UNIX/Linux

<pre><code>java -classpath .:yourjar.jar YourMainClass
</code></pre>

blocks|key|287733|text|如果您使用的是maven，请尝试这些。我在项目中使用maven，当我执行mvn+clean+install并尝试运行程序时，它会抛出异常。所以，我清理了这个项目并再次运行它，它对我来说是有效的。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|287734|我使用eclipse+IDE。|287735|对于运行Junit测试时找不到类的异常，请尝试运行一次mvn+clean+test。它将编译所有的测试类。|287736|entityMap^0|10|H|0|0|R|E|0^^$0|@$1|2|3|4|5|6|7|L|8|@$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@]|D|@]|E|$]]|$1|H|3|I|5|6|7|P|8|@$9|Q|A|R|B|C]]|D|@]|E|$]]|$1|J|3|-4|5|6|7|S|8|@]|D|@]|E|$]]]|K|$]]

Try these if you use maven. I use maven for my project and when I do <code>mvn clean install</code> and try to run a program it throws the exception. So, I clean the project and run it again and it works for me. 

I use eclipse IDE.

For Class Not Found Exception when running Junit test, try running <code>mvn clean test</code> once. It will compile all the test classes.

blocks|key|70169|text|要通过命令行将类的位置添加到类路径中，只需在运行时添加-cp或-classpath和类的位置即可。也就是说。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|70170|java+-cp+"c:/location/of/file"+YourProgram|code-block|syntax|javascript|70171|或者，如果您正在运行诸如eclipse之类的集成开发环境，您可以右键单击project+->+build+path+->+configure+build+path，并将包含您的类的外部JAR添加到构建路径中，然后它就可以正常工作了。|70172|entityMap^0|R|3|V|A|0|0|10|19|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|T|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|U|8|@$9|V|A|W|B|C]]|D|@]|E|$]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

To add the location of a class to your classpath via command line simply add <code>-cp</code> or <code>-classpath</code> and the location of the class while running it. I.E.

<pre><code>java -cp "c:/location/of/file" YourProgram
</code></pre>

Or if you're running an IDE such as eclipse you can right click on the <code>project -&gt; build path -&gt; configure build path</code>
and add the external JAR containing your class to the build path then it should work fine.

blocks|key|287653|text|使用';‘作为分隔符。如果您的环境变量设置正确，您应该会看到您的设置。如果PATH和CLASSPATH正确，windows应该能识别这些命令。安装Java时不需要重新启动计算机。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|287654|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Use ';' as the separator. If your environment variables are set correctly, you should see your settings. If your PATH and CLASSPATH is correct, windows should recognize those commands. You do NOT need to restart your computer when installing Java.

blocks|key|70433|text|基本通用问题--最简单的通用答案;)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|70434|鉴于这些信息，我假设您可能正在尝试一种基本的方法来编码、构建/编译和运行一个简单的控制台应用程序，比如"Hello+World"，使用一些简单的文本编辑器和一些Command+Shell。|70435|此错误发生在休眠场景中：|70436|..\SomePath>javac+HelloWorld.java
..\SomePath>java+HelloWorld.class|code-block|syntax|javascript|70437|换句话说，使用：|70438|..\SomePath>java+HelloWorld|70439|附注:添加文件扩展名.class会产生相同的错误。还要确保在操作系统的环境变量路径中有Java的(JDK/JRE)+bin文件夹。(查找更多详细信息)+P.P.S我的假设是正确的吗？|70440|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|U|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|V|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|W|8|@]|9|@]|A|$]]|$1|M|3|N|5|H|7|X|8|@]|9|@]|A|$I|J]]|$1|O|3|P|5|6|7|Y|8|@]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

Basic Generic Question - Simplest Generic Answer ;)

Given the information I will make the assumption that you might be trying a basic approach to coding, building/compiling and running a simple console app like "Hello World", using some simple text editor and some Command Shell.

This error occurs in the fallowing scenario:

<pre><code>..\SomePath&gt;javac HelloWorld.java
..\SomePath&gt;java HelloWorld.class
</code></pre>

In other words, use:

<pre><code>..\SomePath&gt;java HelloWorld
</code></pre>

P.S. The adding the file extension .class produces the same mistake.
Also be sure to have the Java's (JDK/JRE) bin folder in the operating system's Environment Variables's PATH.(Lookup for more details other posts on this)
P.P.S Was I correct in my assumption/s?

blocks|key|70116|text|转到顶部并删除import语句(如果有)，然后重新导入该类。但如果不是这样，那么就进行一次干净的构建。您使用的是Netbeans还是Eclipse？|type|unstyled|depth|inlineStyleRanges|entityRanges|data|70117|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Go up to the top and remove the import statement if there is one, and re import the class. But if that isn't the case do a clean then build. Are you using Netbeans or Eclipse?

blocks|key|70209|text|我也遇到了这种情况，并尝试了所有其他的解决方案。我的HTML文件夹中没有.class文件，我只有.java文件。一旦我添加了.class文件，程序就可以正常工作了。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|70210|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I ran into this as well and tried all of the other solutions. I did not have the .class file in my HTML folder, I only had the .java file. Once I added the .class file the program worked fine.

blocks|key|287762|text|如果你正在使用maven，试着maven更新所有项目并强制执行快照。它还将清理并重新构建所有类路径。它解决了我的问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|287763|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

If you are using maven 
try to maven update all projects and force for snapshots.
It will clean as well and rebuilt all classpath..
It solved my problem..

blocks|key|70399|text|在java更新后，这可能会在Windows上发生，其中缺少旧版本的java+SDK，但存在新版本。我将检查您的集成开发环境是否使用已安装的java+SDK版本(IntelliJ:+CTRL+%2B+SHIFT+%2B+ALT+%2B+S)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|70400|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

This can happen on Windows after a java update where the old version of the java SDK is missing and a new one is present. I would check if your IDE is using the installed java SDK version (IntelliJ: CTRL + SHIFT + ALT + S)

blocks|key|70362|text|我尝试使用Process类从C#代码运行.jar。java代码在eclipse中运行成功，但在C#+visual+studio中运行不成功，甚至直接点击jar文件，都会因为出现ClassNotFoundException:异常而停止。我的解决方案是将java程序导出为"Runnable+JAR文件“而不是"JAR文件”。希望它能帮助到一些人。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|70363|entityMap^0|5|7|2G|N|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]|$9|K|A|L|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|M|8|@]|D|@]|E|$]]]|G|$]]

I was trying to run .jar from C# code using <code>Process</code> class. The java code ran successfully from eclipse but it doesn't from C# visual studio and even clicking directly on the jar file, it always stopped with <code>ClassNotFoundException:</code> exception. Solution for my, was export the java program as "Runnable JAR file" instead of "JAR File". Hope it can help someone.

blocks|key|70469|text|在我的例子中，作为class+not+found异常抛出的类具有与ssl证书相关的属性。关闭eclipse并以“Run+as+Administrator”打开，然后问题就解决了。由于eclipse已发布相关权限，因此将抛出此类异常。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|70470|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

In my case the class thrown as class not found exception has properties related to ssl certificates. Close the eclipse and open with as “Run as Administrator” then issue got resolved. As eclipse have issue related permission it will throw such kind of exception.

blocks|key|70522|text|在将"Java+Language+Support“插件从Visual+Studio+Code从0.66.0升级到0.67.0之后，我开始遇到这个问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|70523|降级使我可以毫无问题地运行相同的代码。|70524|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

I started having this issue after upgrading the &quot;Java Language Support&quot; plugin from Visual Studio Code from version 0.66.0 to 0.67.0.
Downgrading back allowed me to run the same code without any issue.

blocks|key|288037|text|我在终端运行Java代码，添加Class+Path的解决方案如下：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|288038|>+java+-cp+<JAR+file>+<JAVA+Class+file>|offset|length|style|CODE|288039|例如，c:\code\prototype-app\target\classes>java+-cp+..\prototype-app-1.0-SNAPSHOT.jar+com_stree.app.DetectLabels|288040|我的运行时环境：|288041|操作系统:+Windows+10|288042|*JAVA:+15.0.1|288043|*Maven:+3.8.1|288044|entityMap^0|0|0|13|0|3|2Y|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|T|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|U|8|@$D|V|E|W|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|X|8|@$D|Y|E|Z|F|G]]|9|@]|A|$]]|$1|J|3|K|5|6|7|10|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|11|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|12|8|@]|9|@]|A|$]]|$1|P|3|Q|5|6|7|13|8|@]|9|@]|A|$]]|$1|R|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|S|$]]

I ran the Java code at the Terminal and adding Class Path was solution like this: 
<code>&gt; java -cp &lt;JAR file&gt; &lt;JAVA Class file&gt;</code> 
for example,
<code>c:\code\prototype-app\target\classes&gt;java -cp ..\prototype-app-1.0-SNAPSHOT.jar com_stree.app.DetectLabels </code>
My runtime environment: 
  OS: Windows 10 
  JAVA: 15.0.1 
  Maven: 3.8.1

blocks|key|70693|text|值得注意的是，Java有时会对导致问题的类撒谎。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|70694|如果java试图加载依赖于类B的类A，而无法加载类B，则可能会出现此错误。|70695|在某些情况下，当问题是B时，java报告A类不能被加载。|70696|根据我们的记忆，上一次发生这种情况是在类A包含静态字段或加载类B的静态初始化器时。|70697|因此，在检查了类路径是否正确之后(实际上我在启动时转储了完整的类路径)，然后我对类A执行了二进制裁剪。|70698|我的意思是，我删除了A中一半的代码。|70699|如果它仍然失败，我将删除另一半，依此类推，直到问题消失(希望问题消失)。|70700|entityMap^0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|R|8|@]|9|@]|A|$]]|$1|F|3|G|5|6|7|S|8|@]|9|@]|A|$]]|$1|H|3|I|5|6|7|T|8|@]|9|@]|A|$]]|$1|J|3|K|5|6|7|U|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|V|8|@]|9|@]|A|$]]|$1|N|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|O|$]]

It's worth noting that sometimes Java lies about the Class that is causing the problem.
You can get this error if java tries to load class A which depends on class B and class B can't be loaded.
In some circumstances java reports that class A can't be loaded when the problem is B.
From recollection the last time this occurred was when class A includes a static field or a static initializer that loaded class B.
So after checking your class path is correct (I actually dump the full classpath on startup) I then do a binary chop on class A.
By this I mean, I remove half of the code in A.
If it still fails I remove another half and so on until the problem (hopefully goes away).

blocks|key|70579|text|对不起，我来晚了，但我会用最简单的外行语言向你解释。当你输入'javac+‘时，编译器会检查程序并查找错误，首先要确保你的程序和你在命令提示符下执行的程序在同一个目录下。然后它会为你的程序创建一个.class文件。例如，如果我的程序名是Test.java，那么创建的类文件应该是Test.class，它将在下一行执行。有时.class会用另一个名字来表示你的java，使用这个名字，你就会得到输出。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|70580|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

sorry i am late to the question, but i will explain it to you in the simplest layman language.
When you type 'javac &lt;programname.java&gt;
The compiler checks the program and finds errors, first of all make sure your program is in the same directory as you have executed in the command prompt. Then it creates a. Class file of your program. For ex. If the name of my program was Test.java then the class file created should be Test.class which will be executed in the next line.
Sometimes java takes some other name for your .class, use that name and voila you'll get the output.

blocks|key|287981|text|我删除了一些未使用的导入，它为我解决了这个问题。如果你从一开始就不去寻找一个类，你就不可能找不到它。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|287982|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I deleted some unused imports and it fixed the problem for me. You can't not find a Class if you never look for it in the first place.

blocks|key|287698|text|将所有代码放在try块中，然后在catch块中捕获异常|type|unstyled|depth|inlineStyleRanges|entityRanges|data|287699|try
{
++++//+code
}
catch(ClassNotFoundException+e1)
{
++++e1.getmessage();
}|code-block|syntax|javascript|287700|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Put all the code in try block then catch exception in a catch block

<pre><code>try
{
 // code
}
catch(ClassNotFoundException e1)
{
 e1.getmessage();
}
</code></pre>

I am trying to run a Java application, but getting this error: 

<code>java.lang.ClassNotFoundException:</code> 

After the colon comes the location of the class that is missing. However, I know that that location does not exist since the class is located elsewhere. How can I update the path of that class? Does it have something to do with the class path?

How do I resolve ClassNotFoundException?

集成开发环境

Visual Studio

编译器

Windows

Eclipse

Linux

Java

我正在尝试运行一个Java应用程序，但是得到了这个错误：java.lang.ClassNotFoundException:冒号后面是缺少的类的位置。但是，我知道这个位置并不存在，因为类位于其他地方。如何更新该类的路径？这与类路径有关吗？

问如何解析ClassNotFoundException？
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