static student

1.Class Student

package demo_static;

public class Student {
    private String name;
    private int age;
    private String sex;
    private int stuNumber;
    private static String  classroomNumber;

    public Student() {
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public int getStuNumber() {
        return stuNumber;
    }

    public void setStuNumber(int stuNumber) {
        this.stuNumber = stuNumber;
    }

    public static String getClassroomNumber() {
        return classroomNumber;
    }

    public static void setClassroomNumber(String classroomNumber) {
        Student.classroomNumber = classroomNumber;
    }
    public void Learning(){
        System.out.println("Learning is the duty !");
    }
    public static void Examing(){
        System.out.println("please join the exam!");
    }
}

2.demo_student

package demo_static;

public class demo_student {
    public static void main(String[] args){
        Student one=new Student();
        one.setAge(18);
        one.setName("Alex");
        one.setSex("male");
        one.setStuNumber(49);
        Student.setClassroomNumber("1303");
        one.Learning();
        System.out.println("age: "+one.getAge()+" name: "+one.getName()+" sex: "
                +one.getSex()+" stuNumber: "+one.getStuNumber()+"ClassroomNumber: "+Student.getClassroomNumber());
        Student.Examing();
    }
}

ret:

Learning is the duty !
age: 18 name: Alex sex: male stuNumber: 49ClassroomNumber: 1303
please join the exam!