刚学java,遇到对象数组初始化问题,报错:Exception in thread "main" java.lang.NullPointerException...
题目:有个student类,建立一个student数组,并通过name,email等方式查询。
Student Classmate = new Student[4]; Classmate[0].SetterName("zhangsan"); ...
程序编译没问题,执行时在Classmate[0]处报错:Exception in thread "main" java.lang.NullPointerException...
报错原因:Student Classmate = newStudent[4]只是定义了引用变量,还没有初始化。
正确的初始化方法:
Student Classmate = new Student[4]; Student p1 = new Student(); p1.SetterName("zhangsan"); Classmate[0] = p1;
或者
Student[] Classmate = { new Student("lisi"), new Student("zhangsan"), };