更多"1. import java.io.*;&ensp"的相关试题:
[多项选择] public class SyncTest{ public static void main(String args) { final StringBuffer s1= new StringBuffer(); final StringBuffer s2= new StringBuffer(); new Thread () { public void run() { synchronized(s1) { s2.append(“A”); synchronized(s2) { s2.append(“B”); System.out.print(s1); System.out.print(s2); } } } }.start(); new Thread() { public void run() { synchronized(s2) { s2.append(“C”); synchronized(s1) { s1.append(“D”); System.out.print(s2); System.out.print(s1); } } } }.start(); } } Which two statements are true? ()
A. The program prints “ABBCAD”
B. The program prints “CDDACB”
C. The program prints “ADCBADBC”
D. The output is a non-deterministic point because of a possible deadlock condition.
E. The output is dependent on the threading model of the system the program is running on.
[单项选择] public class Mycircle { public double radius; public double diameter; public void setRadius(double radius) this.radius = radius; this.diameter= radius * 2; } public double getRadius() { return radius; } Which statement is true?()
A. The Mycircle class is fully encapsulated.
B. The diameter of a given MyCircle is guaranteed to be twice its radius.
C. Lines 6 and 7 should be in a synchronized block to ensure encapsulation.
D. The radius of a MyCircle object can be set without affecting its diameter.
[单项选择] public class WhileFoo { public static void main (String []args) { int x= 1, y = 6; while (y--) {x--;} system.out.printIn(“x=” + x “y =” + y); } } What is the result?()
A. The output is x = 6 y = 0
B. The output is x = 7 y = 0
C. The output is x = 6 y = -1
D. The output is x = 7 y = -1
E. Compilation will fail.
[单项选择] public class Threads5 { public static void main (String[] args) { new Thread(new Runnable() { public void run() { System.out.print(”bar”); } }).start(); } } What is the result?()
A. Compilation fails.
B. An exception is thrown at runtime.
C. The code executes normally and prints “bar”.
D. The code executes normally, but nothing prints.
[单项选择] public class Threads4 { public static void main (String[] args) { new Threads4().go(); } public void go() { Runnable r = new Runnable() { public void run() { System.out.print(”foo”); } }; Thread t = new Thread(r); t.start(); t.start(); } } What is the result?()
A. Compilation fails.
B. An exception is thrown at runtime.
C. The code executes normally and prints „foo”.
D. The code executes normally, but nothing is printed.
[多项选择] 1. class Calc { 2. public static void main(String [] args) { 3. try { 4. int x = Integer.parseInt("42a"); 5. //insert code here 6. System.out.print("oops "); 7. } 8. } 9. } 下面哪两行分别插入到第五行,会导致输出“oops”?()
A. } catch (ClassCastException c) {
B. } catch (IllegalStateException c) {
C. } catch (NumberFormatException n) {
D. } catch (IllegalArgumentException e) {
[单项选择] import java.io.IOException; public class ExceptionTest( public static void main (Stringargs) try ( methodA(); ) catch (IOException e) ( system.out.printIn(“Caught IOException”); ) catch (Exception e) ( system.out.printIn(“Caught Exception”); ) ) public void methodA () { throw new IOException (); } What is the result?()
A. The code will not compile.
B. The output is caught exception.
C. The output is caught IOException.
D. The program executes normally without printing a message.
[单项选择] 1.public class test ( 2.public static void main (String args[]) { 3.int i = 0xFFFFFFF1; 4.int j = ~i; 5. 6.} 7.) What is the decimal value of j at line 5?()
A. 0
B. 1
C. 14
D. –15
E. An error at line 3 causes compilation to fail.
F. An error at line 4 causes compilation to fail.
[单项选择] 1.public class Test { 2.public static void main (String args[]) { 3.class Foo { 4.public int i = 3; 5.} 6.Object o = (Object) new Foo(); 7.Foo foo = (Foo)o; 8.System.out.printIn(foo. i); 9. } 10.} What is the result?()
A. Compilation will fail.
B. Compilation will succeed and the program will print “3”
C. Compilation will succeed but the program will throw a ClassCastException at line 6.
D. Compilation will succeed but the program will throw a ClassCastException at line 7.
[多项选择]
下列解释正确的是()
A. out_applet.java中一定有一个参数是“display_string”
B.
具有两个属性“name”和“value”
C. value是参数的名称
D. “good morning”通过
标记传递给“Our_Applet.class”
[简答题] 一般程序如下: ORG 2000H ARY DW --4,3,--2,1 CNT DW $--ARY VAR DW ARY,$+4 ┆ MOV AX,ARY MOV BX,OFFSET VAR MOV CX,CNT MOV DX,VAR+2 LEA SI,ARY ┆ 此程序段执行后,寄存器AX,BX,CX,DX与SI中的内容各是多少?
[单项选择] 现有: 1 Interface F{} 2 class A implements F{} 3 class B extends A{} 4 class C extends B{ 5 public static void main(String[] args){ 6 B b=new B(); 7 //inSert C0de here 8 } 9 } 下列哪行代码插入到第7行,将抛出java.lang.ClassCaseException异常()
A. A a=b;
B. F f= (C)b;
C. F f= (A)b;
D. B bb= (B)(A)b;
[单项选择] 现有: class Pencil { public void write (String content){ System.out.println ("Write"+content); } } class RubberPencil extends Pencil{ public void erase (String content){ System.out.println ("Erase"+content); } } 执行下列代码的结果是哪项?() Pencil pen=new RubberPencil(); pen.write ("Hello"); pen.erase ("Hello");
A. Write Hello Erase Hello
B. Erase Hello Write Hello
C. 编译错误
D. 运行时抛出异常
[多项选择] public class Foo { private int val; public foo(int v) (val = v;) } public static void main (String args) { Foo a = new Foo (10); Foo b = new Foo (10); Foo c = a; int d = 10; double e = 10.0; } Which three logical expression evaluate to true? ()
A. (a ==c)
B. (d ==e)
C. (b ==d)
D. (a ==b)
E. (b ==c)
F. (d ==10.0)
[单项选择] public class Pet{ private String name; public Pet(){ System.out.print(1); } public Pet(String name){ System.out.print(2); } } public class Dog extends Pet{ public Dog(String name){ System.out.print(3); } } 执行new Dog(“棕熊”);后程序输出是哪项?()
A. 23
B. 13
C. 123
D. 321
[单项选择] 现有 public class Parentt public void change (int x){) ) public class Child extends Parent{ //覆盖父类change方法 } 下列哪个声明是正确的覆盖了父类的change方法?()
A. protected void change (int x){}
B. public void change(int x, int y){}
C. public void change (int x){}
D. public void change (String s){}