package school;
public class SchClass {
private Student[] students;
private int numStudents = 0;
public SchClass() {
}
public void addStudent(Student s) {
this.students[this.numStudents] = s;
this.amountStudents++;
}
}
,我试图在另一个类运行此:
import school.SchClass;
import school.Student;
import school.Tutor;
public class JavaTesting {
public static void main(String[] args) {
Student s = new Student();
Tutor t = new Tutor();
SchClass shc = new SchClass();
sch.setTutor(t);
sch.addStudent(s);
}
}
当我做到这一点,它报告此NullPointer异常:
Exception in thread "main" java.lang.NullPointerException
at school.SchClass.addStudent(SchClass.java:8)
at javatesting.JavaTesting.main(JavaTesting.java:10)
什么是错?我确信我编码完美,但仍然报错。
初始化'学生[]数组students'尝试 –
在最少的语法检查代码示例,如果它们应该是完整的代码块。 – luksch