编译时错误 javac: Command not found 包含javac编译器的路径变量设置不正确。 HelloWorldApp.java:3: Method printl (java.lang.String) not found in class java.io.PrintStream. System.out.printl (“Hello World!”); ^ 方法名printl不正确, HelloWorldApp.java:1: Public class HelloW
import java.applet.Applet; import java.awt.Color; import java.awt.Graphics; import java.awt.Rectangle; /** An applet that displays a simple animation */ public class BouncingCircle extends Applet implements Runnable { int x = 150, y = 50, r = 50; //