Q1:下面中哪两个可以在A的子类中使用class A {protected int method1 (int a, int b) {return 0;}}
A. public int method 1 (int a, int b) { return 0; }
B. private int method1 (int a, int b) { return 0; }
C. private int method1 (int a, long b) { return 0; }
D. public short method1 (int a, int b) { return 0; }
Q2:下列说法正确的有( )
A. class中的constructor不可省略
B. constructor必须与class同名,但方法不能与class同名
C. constructor在一个对象被new时执行
D.一个class可以定义多个constructor
Q3:覆盖与重载的关系是 ( )
A、覆盖只有发生在父类与子类之间,而重载可以发生在同一个类中
B.覆盖方法可以不同名,而重载方法必须同名
C.final修饰的方法可以被覆盖,但不能被重载
D.覆盖与重载是同一回事
Q5:5. 重载(overload)和重写(override)的区别?
填空1
Q6:以下代码的输出结果正确的是( )public static int demo5() { try { return printX(); } finally { System.out.println(finally trumps return... sort of); } } public static int printX() { System.out.println(X); return 0; }
A. X finally trumps return... sort of 0
B. X 0 finally trumps return... sort of
C. finally trumps return... sort of X 0
D. finally trumps return... sort of 0 X
Q7:下面关于finally的说法正确的是
A. 无论在什么情况下,finally块中代码都会执行;
B. 函数返回值是在finally执行前确定的;
C. finally中最好不要包含return,否则程序会提前退出,返回值不是try或catch中保存的返回值。
D. 先执行try块,出现异常后执行finally块,最后向调用者抛出try中的异常
Q9:以下代码的输出结果正确的是( )public static void main(String[] args) { System.out.println(test());}public static String test() { try { System.out.println(try block); return test1(); } finally { System.out.println(finally block); }}public static String test1() { System.out.println(return statement); return after return;}
A. try block finally block return statement after return
B. try block return statement finally block after return
C. try block finally block after return return statement
D. return statement after return try block finally block
Q10:下列哪个选项的结论是错误的?
A、int num = 1; int num1 = 1; System.out.println(num==num1); 输出结果为true
B、 Integer num2 = new Integer("1"); Integer num3 = new Integer("1"); System.out.println(num2==num3); System.out.println(num2.equals(num3)); 输出结果为false、true
C、String s = "hello"; String s1 = "hello"; System.out.println(s==s1); System.out.println(s.equals(s1)); 输出结果为false、true
D、 Account account = new Account(); //该类中未重写equals()方法 Account account1 = new Account(); System.out.println(account==account1); System.out.println(account.equals(account1)); 输出结果为false、false