JAVA小程序在myeclipse下调试输入正确的数据没有提示输入的身份证合法

package example;
import javax.swing.JOptionPane;

public class Identity {

public static void main(String[] args) {
    // TODO Auto-generated method stub
    String ID;
    int year,month,day,lent,province;
    ID=JOptionPane.showInputDialog("请输入你的身份证号：");
    lent=ID.length();
    if(lent!=18){
        JOptionPane.showMessageDialog(null, "身份证长度输入错误","warning",0);
        return ;
    }
    province=Integer.parseInt(ID.substring(0,2));
    year=Integer.parseInt(ID.substring(6,10));
    month=Integer.parseInt(ID.substring(10,12));
    day=Integer.parseInt(ID.substring(12,14));
    int array[]={0,31,28,31,30,31,30,31,31,30,31,30,31};

    if (province<=00||province>=51){
        JOptionPane.showMessageDialog(null, "省市错误","warning",0);
    }
    else if(year<=1500||year>2015){
        JOptionPane.showMessageDialog(null, "年份错误","warning",0);
    }
    else if(month<1||month>12){
        JOptionPane.showMessageDialog(null, "月份错误","warning",0);
    }
    else if(year%400==0||year%4==0&&year%100!=0){
        if(month==2&&(day>29||day<=0)){
            JOptionPane.showMessageDialog(null, "日子错误","warning",0);
        }
    }
    else if(array[month]<=day||day<=0){
        JOptionPane.showMessageDialog(null, "日子错误","warning",0);
    }
    else
        JOptionPane.showMessageDialog(null, "身份证输入合法","Yes",JOptionPane.PLAIN_MESSAGE);;
}

}