超星 - 新建作业20211219150138

单选题

程序的输出结果为：（）。class A{final public int GetResult(int a, int b) { return 0; }} class B extends A{public int GetResult(int a, int b) {return 1; }} public class Test{public static void main(String args[]){B b = new B();System.out.println("x = " + b.GetResult(0, 1));}}

A. x = 0
B. x = 1
C. 编译错误
D. 运行时异常

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单选题

以下程序的输出结果为：（）class SC2{public static void main(String [] args){SC2 s = new SC2();s.start();}void start(){int a = 3;int b = 4;System.out.print(" " + 7 + 2 + " ");System.out.print(a + b);System.out.print(" " + a + b + " ");System.out.print(foo() + a + b + " ");System.out.println(a + b + foo());}String foo(){return "foo";}}

A. 9 7 7 foo 7 7foo
B. 72 34 34 foo34 34foo
C. 9 7 7 foo34 34foo
D. 72 7 34 foo34 7foo

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单选题

以下程序的输出结果为：（）class BoolArray{boolean [] b = new boolean[3];int count = 0;void set(boolean [] x, int i){x[i] = true;++count;}public static void main(String [] args){BoolArray ba = new BoolArray();ba.set(ba.b, 0);ba.set(ba.b, 2);ba.test();}void test(){if ( b[0] && b[1] | b[2] )count++;if ( b[1] && b[(++count - 2)] )count += 7;System.out.println("count = " + count);}}

A. count = 0
B. count = 2
C. count = 3
D. count = 4

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单选题

public void foo( boolean a, boolean b){if( a ){System.out.println("A"); /* Line 5 /}else if(a && b) / Line 7 /{System.out.println( "A && B");}else / Line 11 */{if ( !b ){System.out.println( "notB") ;}else{System.out.println( "ELSE" ) ;}}}

A. If a is true and b is true then 输出 "A && B"
B. If a is true and b is false then 输出 "notB"
C. If a is false and b is true then 输出 "ELSE"
D. If a is false and b is false then 输出 "ELSE"

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单选题

以下程序的输出结果为：（）public class Test{public static void aMethod() throws Exception{try/* Line 5 /{throw new Exception();/ Line 7 /}finally/ Line 9 /{System.out.print("finally ");/ Line 11 /}}public static void main(String args[]){try{aMethod();}catch (Exception e) / Line 20 /{System.out.print("exception ");}System.out.print("finished");/ Line 24 */}}

A. finally
B. exception finished
C. finally exception finished
D. Compilation fails

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单选题

class X implements Runnable{public static void main(String args[]){/* Missing code? */}public void run() {}}哪一行代码适合启动线程？

A. Thread t = new Thread(X);
B. Thread t = new Thread(X);t.start();
C. X run = new X();Thread t = new Thread(run);t.start();
D. Thread t = new Thread();x.run();

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单选题

以下程序的输出结果为：（）class MyThread extends Thread{MyThread() {}MyThread(Runnable r) {super(r); }public void run(){System.out.print("Inside Thread ");}}class MyRunnable implements Runnable{public void run(){System.out.print(" Inside Runnable");}}class Test{public static void main(String[] args){new MyThread().start();new MyThread(new MyRunnable()).start();}}

A. 输出 "Inside Thread Inside Thread"
B. 输出 "Inside Thread Inside Runnable"
C. 不会编译
D. 运行时异常

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单选题

以下程序的输出结果为：（）class s implements Runnable{int x, y;public void run(){for(int i = 0; i < 1000; i++)synchronized(this){x = 12;y = 12;}System.out.print(x + " " + y + " ");}public static void main(String args[]){s run = new s();Thread t1 = new Thread(run);Thread t2 = new Thread(run);t1.start();t2.start();}}

A. 死锁
B. 12 12 12 12
C. 编译错误
D. 没有输出

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单选题

以下程序的输出结果为：（）public class NFE{public static void main(String [] args){String s = "42";try{s = s.concat(".5");/* Line 8 */double d = Double.parseDouble(s);s = Double.toString(d);int x = (int) Math.ceil(Double.valueOf(s).doubleValue());System.out.println(x);}catch (NumberFormatException e){System.out.println("bad number");}}}

A. 42
B. 42.5
C. 43
D. bad number

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单选题

以下程序输出结果为：（）public class ArrayTest{public static void main(String[ ] args){float f1[ ], f2[ ];f1 = new float[10];f2 = f1;System.out.println("f2[0] = " + f2[0]);}}

A. f2[0] = 0.0
B. f2[0] = NaN
C. 编译错误
D. 不确定值

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程序的输出结果为：（）。class A{final public int GetResult(int a, int b) { return 0; }} class B extends A{public int GetResult(int a, int b) {return 1; }} public class Test{public static void main(String args[]){B b = new B();System.out.println("x = " + b.GetResult(0, 1));}}

public void foo( boolean a, boolean b){if( a ){System.out.println("A"); /* Line 5 */}else if(a && b) /* Line 7 */{System.out.println( "A && B");}else /* Line 11 */{if ( !b ){System.out.println( "notB") ;}else{System.out.println( "ELSE" ) ;}}}

class X implements Runnable{public static void main(String args[]){/* Missing code? */}public void run() {}}哪一行代码适合启动线程？

以下程序输出结果为：（）public class ArrayTest{public static void main(String[ ] args){float f1[ ], f2[ ];f1 = new float[10];f2 = f1;System.out.println("f2[0] = " + f2[0]);}}

public void foo( boolean a, boolean b){if( a ){System.out.println("A"); /* Line 5 /}else if(a && b) / Line 7 /{System.out.println( "A && B");}else / Line 11 */{if ( !b ){System.out.println( "notB") ;}else{System.out.println( "ELSE" ) ;}}}