Oracle 1Z0-803 問題集

質問 1：
Given:
interface Pet { }
class Dog implements Pet { }
public class Beagle extends Dog{ }
Which three are valid?
A. Beagle c = new Dog();
B. Dog d = new Beagle();
C. Pet e = new Beagle();
D. Dog f = new Pet();
E. Pet a = new Dog();
F. Pet b = new Pet();
正解：B,C,E
解説: (Topexam メンバーにのみ表示されます)

質問 2：
Which two will compile, and can be run successfully using the command:
Java fred1 hello walls

A. Option A
B. Option C
C. Option D
D. Option B
正解：B,C
解説: (Topexam メンバーにのみ表示されます)

質問 3：
Which two actions will improve the encapsulation of a class?
A. Returning a copy of the contents of an array or ArrayList instead of a direct reference
B. Changing the access modifier of a field from public to private
C. Removing the public modifier from a class declaration
D. Changing the return type of a method to void
正解：A,B
解説: (Topexam メンバーにのみ表示されます)

質問 4：
View the Exhibit.
public class Hat {
public int ID =0;
public String name = "hat";
public String size = "One Size Fit All";
public String color="";
public String getName() { return name; }
public void setName(String name) {
this.name = name;
}
}
Given
public class TestHat {
public static void main(String[] args) {
Hat blackCowboyHat = new Hat();
}
}
Which statement sets the name of the Hat instance?
A. Hat.setName("Cowboy Hat");
B. blackCowboyHat.setName("Cowboy Hat");
C. blackCowboyHat.setName = "Cowboy Hat";
D. setName("Cowboy Hat");
正解：B

質問 5：
UESTION NO: 96 Which two statements are true for a two-dimensional array?
A. At declaration time, the number of elements of the array in each dimension must be specified.
B. It is implemented as an array of the specified element type.
C. All methods of the class Object may be invoked on the two-dimensional array.
D. Using a row by column convention, each row of a two-dimensional array must be of the same size.
正解：B,C

質問 6：
Given the code fragment:
int [][] array2d = new int[2][3];
System.out.println("Loading the data.");
for ( int x = 0; x < array2d.length; x++) {
for ( int y = 0; y < array2d[0].length; y++) {
System.out.println(" x = " + x);
System.out.println(" y = " + y);
// insert load statement here.
}
}
System.out.println("Modify the data. ");
for ( int x = 0; x < array2d.length; x++) {
for ( int y = 0; y < array2d[0].length; y++) {
System.out.println(" x = " + x);
System.out.println(" y = " + y);
// insert modify statement here.
}
}
Which pair of load and modify statement should be inserted in the code?
The load statement should set the array's x row and y column value to the sum of x and y
The modify statement should modify the array's x row and y column value by multiplying it by 2
A. Load statement: array2d[x][y] = x + y;
Modify statement: array2d[x][y] = array2d[x][y] * 2
B. Load statement: array2d(x, y) = x + y;
Modify statement: array2d(x, y) = array2d(x, y) * 2
C. Load statement: array2d[[x][y]] = x + y;
Modify statement: array2d[[x][y]] = array2d[[x][y]] * 2
D. Load statement: array2d[x, y] = x + y;
Modify statement: array2d[x, y] = array2d[x, y] * 2
E. Load statement: array2d[x y] = x + y;
Modify statement: array2d[x y] = array2d[x y] * 2
正解：A

質問 7：
Give:
Public Class Test {
}
Which two packages are automatically imported into the java source file by the java compiler?
A. Java.util
B. Java.lang
C. The package with no name
D. Javax.net
E. Java.*
F. Java.awt
正解：B,C
解説: (Topexam メンバーにのみ表示されます)

質問 8：
Which two are Java Exception classes?
A. IllegalArgumentException
B. TooManyArgumentsException
C. DuplicatePathException
D. SercurityException
正解：A,D