Unicode和老编码体系的转化过程中，肯定有一些字，用Unicode是没法表示的，Unicode官方用了一个占位符来表示这些文字，这就是：U+FFFD REPLACEMENT CH

[14:56:27] [main/INFO] [LaunchWrapper]: Loading tweak class name net.minecraftforge.fml.common.launcher.FMLTweaker [14:56:27] [main/INFO] [LaunchWrapper]: Using primary tweak class name net.minecraftforge.fml.common.launcher.FMLTweaker [14:56:27] [main/INFO] [LaunchWrapper]: Loading tweak class name optifine.OptiFineForgeTweaker [14:56:27] [main/INFO] [LaunchWrapper]: Calling tweak class net.minecraftforge.fml.common.launcher.FMLTweaker [14:56:27] [main/INFO] [FML]: Forge Mod Loader version 14.23.5.2860 for Minecraft 1.12.2 loading [14:56:27] [main/INFO] [FML]: Java is Java HotSpot(TM) 64-Bit

[19:07:24] [main/INFO] [LaunchWrapper]: Loading tweak class name net.minecraftforge.fml.common.launcher.FMLTweaker [19:07:24] [main/INFO] [LaunchWrapper]: Using primary tweak class name net.minecraftforge.fml.common.launcher.FMLTweaker [19:07:24] [main/INFO] [LaunchWrapper]: Calling tweak class net.minecraftforge.fml.common.launcher.FMLTweaker [19:07:24] [main/INFO] [FML]: Forge Mod Loader version 14.23.5.2860 for Minecraft 1.12.2 loading [19:07:24] [main/INFO] [FML]: Java is Java HotSpot(TM) 64-Bit Server VM, version 1.8.0_311, running on Windows 10:amd64:10.0, installed at C:\Program Files\J

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at javax.swing.text.WrappedPlainView$WrappedLine.paint(Unknown Source)
at javax.swing.text.BoxView.paintChild(Unknown Source)
at javax.swing.text.BoxView.paint(Unknown Source)
at javax.swing.text.WrappedPlainView.paint(Unknown Source)
at javax.swing.plaf.basic.BasicTextUI$RootView.paint(Unknown Source)
at javax.swing.plaf.basic.BasicTextUI.paintSafely(Unknown Source)
at javax.swing.plaf.basic.BasicTextUI.paint(Unknown Source)
at javax.swing.plaf.basic.BasicTextUI.update(Unknown Source)
at javax.swing.JComponent.paintComponent(Unknown Source)
at javax.swing.JComponent.paint(Unknown Source)
at javax.swing.JComponent.paintToOffscreen(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paintDoubleBuffered(Unknown Source)
at javax.swing.RepaintManager$PaintManager.paint(Unknown Source)
at javax.swing.RepaintManager.paint(Unknown Source)
at javax.swing.JComponent._paintImmediately(Unknown Source)
at javax.swing.JComponent.paintImmediately(Unknown Source)
at javax.swing.RepaintManager$4.run(Unknown Source)
at javax.swing.RepaintManager$4.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.paintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.prePaintDirtyRegions(Unknown Source)
at javax.swing.RepaintManager.access$1200(Unknown Source)
at javax.swing.RepaintManager$ProcessingRunnable.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
at java.awt.EventQueue.access$500(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.awt.EventQueue$3.run(Unknown Source)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

问：Applet和普通的Java应用程序有什么区别？
答：Applet是运行在启用了Java的浏览器中，Java应用程序是可以在浏览器之外运行的独立的Java程序。但是，它们都需要有Java虚拟机。进一步来说，Java应用程序需要一个有特定方法签名的main函数来开始执行。Java Applet不需要这样的函数来开始执行。最后，JavaApplet一般会使用很严格的安全策略，Java应用一般使用比较宽松的安全策略。

你要是女的就是学起来不男， 要是男的就学起来男，

昨天已经折腾了一天了，本以为从eclipse1.6换到eclipse1.8就解决了，结果只是发生的概率更低了，今天在我调试考试按钮的时候又出现了！！！

完了，一个新手要被这个错误杀死了

你看了刚开始，都是些定义和计算，当然差不多，c没有类，不能重载，不能泛型，没有jvm帮你收尸，java不能直接操作内存，速度比c慢

就第四个正常点，其他是不是表达有问题？