在Eclipse中运行时找不到类

Question

尝试在Eclipse中运行我的项目，但它创建了以下错误：

Apr 11, 2014 8:02:17 AM net.minecraft.launchwrapper.LogWrapper log
INFO: Loading tweak class name cpw.mods.fml.common.launcher.FMLTweaker
Apr 11, 2014 8:02:21 AM net.minecraft.launchwrapper.LogWrapper log
SEVERE: Unable to launch
java.lang.ClassNotFoundException: cpw.mods.fml.common.launcher.FMLTweaker
      at java.net.URLClassLoader$1.run(Unknown Source)
      at java.net.URLClassLoader$1.run(Unknown Source)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(Unknown Source)
      at java.lang.ClassLoader.loadClass(Unknown Source)
      at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
      at java.lang.ClassLoader.loadClass(Unknown Source)
      at net.minecraft.launchwrapper.LaunchClassLoader.findClass(LaunchClassLoader.java:102)
      at java.lang.ClassLoader.loadClass(Unknown Source)
      at java.lang.ClassLoader.loadClass(Unknown Source)
      at java.lang.Class.forName0(Native Method)
      at java.lang.Class.forName(Unknown Source)
      at net.minecraft.launchwrapper.Launch.launch(Launch.java:94)
      at net.minecraft.launchwrapper.Launch.main(Launch.java:27)

但是我的项目中包含了所有的文件。

这是一个与this非常相似的问题，但我尝试了刷新类路径的解决方案，但它不起作用。有什么建议吗？

在进阶时谢谢！

Answer 1

如果您不确定是否导入了所有必需的包，请在引发此错误的类中按Ctrl + Shift +O，然后导入所有必需的包并重新编译代码。

Answer 2

This problem clearly specifies it lacks class files.

Steps to narrow done this problem : 

First Approach
By clicking - Ctrl+Shift+T
Paste the package name cpw.mods.fml.common.launcher.FMLTweaker, you should be able to figure out, which jar/source file hold this.


Second Approach
Go to Build Path->Configure Build Path ->Order and Export-> Arrange the folders according to the sequence they have to be loaded. (Sometimes if A expects B but B is loaded after A, causes this issue)


Third Approach
Try to import the packages using Ctrl+Shift+o , which automatically gives the suggestions to select from . Pick the right one.

Fourth Approach,
This might be even happening because of the same name class conflicts.(Same Class Name used in multiples jars/source files) . Import the right package one from it.