關於jbuilder9的問題
我把jdk改成1.5或1.6時運行就會顯示"numberguess.java": cannot access javax.swing.JOptionPane,bad class file: D:\Program Files\Java\jdk1.6.0\jre\lib\rt.jar\javax\swing\JOptionPane.class,class file has wrong version 49.0, should be 48.0,Please remove or make sure it appears in the correct subdirectory of the classpath. at line 1, column 20
請問怎解決```急啊
