Which two construct ...

多项选择题Which two construct an OutputSream that appends to the file “file.txt”？（）

A. OutputStream out=new FileOutputStream（“file.txt”）；
B. OutputStream out=new FileOutputStream（“file.txt”， “append”）；
C. FileOutputStream out=new FileOutputStream（“file.txt”， true）；
D. FileOutputStream out=new FileOutputStream（new file（“file.txt”））；
E. OutputStream out=new FileOutputStream（new File（“file.txt”）true）；

点击查看答案

您可能感兴趣的试卷

你可能感兴趣的试题

1.多项选择题Which two create an InputStream and open file the “file.txt” for reading？（）

A. InputStream in=new FileReader（“file.txt”）；
B. InputStream in=new FileInputStream（“file.txt”）；
C. InputStream in=new InputStreamFileReader （“file.txt”， “read”）；
D. FileInputStream in=new FileReader（new File（“file.txt”））；
E. FileInputStream in=new FileInputStream（new File（“file.txt”））；

点击查看答案

2.单项选择题Which determines if “prefs” is a directory and exists on the file system？（）

A. Boolean exists=Directory.exists （“prefs”）；
B. Boolean exists=（new File（“prefs”））.isDir（）；
C. Boolean exists=（new Directory（“prefs”））.exists（）；
D. Boolean exists=（new File（“prefs”））.isDirectory（）；
E. Boolean exists=true； Try{ Directory d = new Directory（“prefs”）； } catch （FileNotFoundException e） { exists = false； }

点击查看答案

3.单项选择题 class super {
public int getLength（） {return 4；}
}
public class Sub extends Super {
public long getLength（） {return 5；}
public static void main （Stringargs） {
super sooper = new Super （）；
Sub sub = new Sub（）；
System.out.printIn（
sooper.getLength（）+ “，” + sub.getLength（） }；
}
What is the output？（）

A. 4， 4
B. 4， 5
C. 5， 4
D. 5， 5
E. The code will not compile.

点击查看答案

4.多项选择题Which two statements are true regarding the creation of a default constructor？（）

A. The default constructor initializes method variables.
B. The compiler always creates a default constructor for every class.
C. The default constructor invokes the no-parameter constructor of the superclass.
D. The default constructor initializes the instance variables declared in the class.
E. When a class has only constructors with parameters， the compiler does not create a default constructor.

点击查看答案

5.单项选择题 public class ArrayTest {
public static void main （Stringargs） {
float f1， f2；
f1 = new float [10]；
f2 = f1；
System.out.printIn （“f2[0]=” + f2[0]）；
}
}
What is the result？（）

A. It prints f2[0] = 0.0
B. It prints f2[0] = NaN
C. An error at line 5 causes compile to fail.
D. An error at line 6 causes compile to fail.
E. An error at line 6 causes an exception at runtime.

点击查看答案

6.单项选择题 ClassOne.java
package com.abc.pkg1；
public class ClassOne {
private char var = ‘a‘；
char getVar（） {return var；}
}
ClassTest.java
package com.abc.pkg2；
import com.abc.pkg1.ClassOne；
public class ClassTest extends ClassOne {
public static void main（Stringargs） {
char a = new ClassOne（）.getVar（）；
char b = new ClassTest（）.getVar（）；
}
}
What is the result？（）

A. Compilation will fail.
B. Compilation succeeds and no exceptions are thrown.
C. Compilation succeeds but an exception is thrown at line 5 in ClassTest.java.
D. Compilation succeeds but an exception is thrown at line 6 in ClassTest.java.

点击查看答案

7.单项选择题You want to limit access to a method of a public class to members of the same class. Which access modifier accomplishes this objective？（）

A. Public
B. Private
C. Protected
D. Transient
E. No access modifier is required

点击查看答案

8.单项选择题 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.

点击查看答案

9.多项选择题Which two statements are true？（）

A. An inner class may be declared as static.
B. An anonymous inner class can be declared as public.
C. An anonymous inner class can be declared as private.
D. An anonymous inner class can extend an abstract class.
E. An anonymous inner class can be declared as protected.

点击查看答案

10.多项选择题 AnInterface is an interface.
AnAdapter0 is a non-abstract， non-final class with a zero argument constructor.
AnAdapter1 is a non-abstract， non-final class without a zero argument constructor， but with a constructor that takes one int argument.
Which two construct an anonymous inner class？（）

A. AnAdapter1 aa=new AnAdapter1（）{}
B.AnAdapter0 aa=new AnAdapter0（）{}
C. AnAdapter0 aa=new AnAdapter0（5）{}
D. AnAdapter1 aa=new AnAdapter1（5）{}
E.AnInterface a1=new AnInterface（5）{}

点击查看答案