x = y;
z = x;
y = (B) x;
z = (C) y;
y = (A) y;
第1题:
In which two cases does the compiler supply a default constructor for class A?()
第2题:
Which statements concerning the following code are true?() class a { public a() {} public a(int i) { this(); } } class b extends a { public boolean b(String msg) { return false; } } class c extends b { private c() { super(); } public c(String msg) { this(); } public c(int i) {} }
第3题:
A.public class MinMax<?> {
B.public class MinMax<? extends Number> {
C.public class MinMax<N extends Object> {
D.public class MinMax<N extends Number> {
E.public class MinMax<? extends Object> {
F.public class MinMax<N extends Integer> {
第4题:
Given the following class, which statements can be inserted at position 1 without causing the code to fail compilation?() public class Q6db8 { int a; int b = 0; static int c; public void m() { int d; int e = 0; // Position 1 } }
第5题:
Which statements, when inserted at the indicated position in the following code, will cause a runtime exception when attempting to run the program?() class A {} class B extends A {} class C extends A {} public class Q3ae4 { public static void main(String args[]) { A x = new A(); B y = new B(); C z = new C(); // insert statement here } }
第6题:
Which statements can be inserted at the indicated position in the following code to make the program write 1 on the standard output when run?() public class Q4a39 { int a = 1; int b = 1; int c = 1; class Inner { int a = 2; int get() { int c = 3; // insert statement here return c; } } Q4a39() { Inner i = new Inner(); System.out.println(i.get()); } public static void main(String args[]) { new Q4a39(); } }
第7题:
interface Data { public void load(); } abstract class Info { public abstract void load(); } Which class correctly uses the Data interface and Info class?()
第8题:
class One { public One() { System.out.print(1); } } class Two extends One { public Two() { System.out.print(2); } } class Three extends Two { public Three() { System.out.print(3); } } public class Numbers{ public static void main( String[] argv) { new Three(); } } What is the result when this code is executed?()
第9题:
class TestA { public void start() { System.out.println(”TestA”); } } public class TestB extends TestA { public void start() { System.out.println(”TestB”); } public static void main(String[] args) { ((TestA)new TestB()).start(); } } What is the result?()
第10题:
public class ExceptionTest { class TestException extends Exception {} public void runTest () throws TestException {} public void test () /* Point X*/ { runTest (); } } At point X on line 4, which code can be added to make the code compile?()