import javax.swing.JOptionPane的问题

简单程序在MyEclipse上无法运行求解决

程序如下

    import javax.swing.JOptionPane;
    public class WelcomInMessageDialogBox {
public static void main(String[] args){
JoptionPane.showMessageDialog(null,"welcome to Java!");
 }
}

错误原因：Access restriction: The type JOptionPane is not accessible due to restriction on required library D:\Myeclipse\Common\binary\com.sun.java.jdk.win32.x86_1.6.0.013\jre\lib\rt.jar

解决办法是：MyEclipse中创建工程中jre不应该选择Use an execution enviorment  Jre

而应该选自己的use default jre currently jdk 1.8（自己安装的jdk）