class A { public int getNumber(int a) { return a + 1; } } class B extends A { public int getNumber (int a) { return a + 2 } public static void main (String args) { A a = new B(); System.out.printIn(a.getNumber(0)); } } What is the result? ()
第1题:
能将程序补充完整的选项是 class Person { private int a; public int change(int m){return m; } } public class Teacher extends Person { public int b; public static void main(String arg[]) { Person p=new Person(); Teacher t=new Teacher(); int i; ______ } }
A.i=m
B.i=b
C.i=p.a
D.i=p.change(50)
第2题:
下列程序的执行结果是 ( ) public class ex68{ public static void main(String[]args){ ex68 obj=new ex68(); int s=0; for(int i=1;i<=4;i++){ s+=obj.method(i); } System.out.println(s); } public int method(int n){ if(n==1) return 1; else return n*method(n-1); } }
A.3
B.9
C.33
D.153
第3题:
1. public class Target { 2. private int i = 0; 3. public int addOne() { 4. return ++i; 5. } 6. } And: 1. public class Client { 2. public static void main(String[] args) { 3. System.out.println(new Target().addOne()); 4. } 5. } Which change can you make to Target without affecting Client?()
第4题:
class super { public int getLength() {return 4;} } public class Sub extends Super { public long getLength() {return 5;} public static void main (String[]args) { super sooper = new Super (); Sub sub = new Sub(); System.out.printIn( sooper.getLength()+ “,” + sub.getLength() }; } What is the output?()
第5题:
class A { public byte getNumber () { return 1; } } class B extends A { public short getNumber() { return 2; } public static void main (String args) { B b = new B (); System.out.printIn(b.getNumber()) } } What is the result?()
第6题:
public class test( public int aMethod()[ static int i=0; i++; return I; ) public static void main (String args){ test test = new test(); test.aMethod(); int j = test.aMethod(); System.out.printIn(j); ] } What is the result?()
第7题:
1) class Person { 2) public void printValue(int i, int j) {/*…*/ } 3) public void printValue(int i){/*...*/ } 4) } 5) public class Teacher extends Person { 6) public void printValue() {/*...*/ } 7) public void printValue(int i) {/*...*/} 8) public static void main(String args[]){ 9) Person t = new Teacher(); 10) t.printValue(10); 11) } 12) } Which method will the statement on line 10 call? ()
第8题:
class A { public byte getNumber() { return 1; } } class B extends A { public short getNumber() { return 2; } public static void main(String args[]) { B b = new B(); System.out.println(b.getNumber()); } } What is the result?()
第9题:
1
2
An exception is thrown at runtime.
Compilation fails because of an error in line 8.
Compilation fails because of an error in line 14.
第10题:
0
1
2
Compilation fails.
第11题:
4, 4
4, 5
5, 4
5, 5
The code will not compile.
第12题:
The program prints “0”
The program prints “4”
The program prints “8”
The program prints “12”
The code does not complete.
第13题:
interface A{
int x = 0;
}
class B{
int x =1;
}
class C extends B implements A {
public void pX(){
System.out.println(x);
}
public static void main(String[] args) {
new C().pX();
}
}
错误。在编译时会发生错误(错误描述不同的JVM 有不同的信息,意思就是未明确的
x 调用,两个x 都匹配(就象在同时import java.util 和java.sql 两个包时直接声明Date 一样)。
对于父类的变量,可以用super.x 来明确,而接口的属性默认隐含为 public static final.所以可
以通过A.x 来明确。
第14题:
1. class A { 2. public int getNumber(int a) { 3. return a + 1; 4. } 5. } 6. 7. class B extends A { 8. public int getNumber (int a) { 9. return a + 2 10. } 11. 12. public static void main (String args[]) { 13. A a = new B(); 14. System.out.printIn(a.getNumber(0)); 15. } 16. } What is the result?()
第15题:
Which are syntactically valid statement at// point x?() class Person { private int a; public int change(int m){ return m; } } public class Teacher extends Person { public int b; public static void main(String arg[]){ Person p = new Person(); Teacher t = new Teacher(); int i; // point x } }
第16题:
class Super { public int i = 0; public Super(String text) { i = 1; } } public class Sub extends Super { public Sub(String text) { i = 2; } public static void main(String args[]) { Sub sub = new Sub(“Hello”); System.out.println(sub.i); } } What is the result?()
第17题:
public class Test { public static void leftshift(int i, int j) { i<<=j; } public static void main(String args[]) { int i = 4, j = 2; leftshift(i, j); System.out.printIn(i); } } What is the result?()
第18题:
public class Test { public int aMethod() { static int i = 0; i++; return i; } public static void main (String args[]) { Test test = new Test(); test.aMethod(); int j = test.aMethod(); System.out.println(j); } } What is the result?()
第19题:
public class test ( private static int j = 0; private static boolean methodB(int k) ( j += k; return true; ) public static void methodA(int i)( boolean b: b = i < 10 | methodB (4); b = i < 10 || methodB (8); ) public static void main (String args[])( methodA (0); system.out.printIn(j); ) ) What is the result?()
第20题:
class super ( public int I = 0; public super (string text) ( I = 1 ) ) public class sub extends super ( public sub (string text) ( i= 2 ) public static void main (straing args) ( sub sub = new sub (“Hello”); system.out. PrintIn(sub.i); ) ) What is the result?()
第21题:
i = m;
i = b;
i = p.a;
i = p.change(30);
i = t.b.
第22题:
0
1
2
Compilation fails.
第23题:
2
4
8
16
The code will not compile.