后台类是否会在类图中呈现？

是的，后台类可以在类图中呈现。以下是一个例子：

public class Employee {
    private int employeeId;
    private String name;
    private String department;

    public Employee(int employeeId, String name, String department) {
        this.employeeId = employeeId;
        this.name = name;
        this.department = department;
    }

    public int getEmployeeId() {
        return employeeId;
    }

    public void setEmployeeId(int employeeId) {
        this.employeeId = employeeId;
    }

    public String getName() {
        return name;
    }

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

    public String getDepartment() {
        return department;
    }

    public void setDepartment(String department) {
        this.department = department;
    }
}

在这个例子中，Employee类包含三个私有实例变量和一些公有方法。我们可以用以下方式将它表示在UML类图中：

注意，根据实际情况，UML类图可以包含更多或更少的信息，但通常会在类的名称下方列出类的属性和方法。