这是程序:class WQ { public static void main(String[] args) { System.out.println("Hello World!"); }}环境变量:JAVA_HOME:E:\java\jdk1.7Path:%JAVA_HOME%\bin;%JAVA_HOME%\jre\bin;CLASSPATH:.;JAVA_HOME%\lib\dt.jar;%JAVA_HOME%\lib\tools.jar;