Oracle 1Z0-803 問題集

質問 1：
Which two are valid instantiations and initializations of a multi dimensional array?

A. Option E
B. Option A
C. Option C
D. Option D
E. Option B
正解：B,D

質問 2：
Given the code fragment:
int a = 0; a++;
System.out.printIn(a++);
System.out.printIn(a);
What is the result?
A. 2 2
B. 1 2
C. 1 1
D. 0 1
正解：B
解説: (Topexam メンバーにのみ表示されます)

質問 3：
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 4：
What is the proper way to defined a method that take two int values and returns their sum as an int value?
A. int sum(int first, int second) { return first + second; }
B. int sum(int first, int second) { first + second; }
C. sum(int first, int second) { return first + second; }
D. void sum (int first, int second) { return first + second; }
E. int sum(int first, second) { return first + second; }
正解：A

質問 5：
Given:

Which statement, when inserted into line 5, is valid change?
A. asc = sc.clone ()
B. asc = sc;
C. asc = (object) sc;
D. sc = asc;
正解：D
解説: (Topexam メンバーにのみ表示されます)

質問 6：
Given:
public class ComputeSum {
public int x;
public int y;
public int sum;
public ComputeSum (int nx, int ny) {
x = nx; y =ny;
updateSum();
}
public void setX(int nx) { x = nx; updateSum();}
public void setY(int ny) { x = ny; updateSum();}
void updateSum() { sum = x + y;}
}
This class needs to protect an invariant on the sum field.
Which three members must have the private access modifier to ensure that this invariant is maintained?
A. The y field
B. The setY ( ) method
C. The sum field
D. The ComputerSum ( ) constructor
E. The x field
F. The setX ( ) method
正解：B,C,F
解説: (Topexam メンバーにのみ表示されます)

質問 7：
Given:

Which constructor initializes the variable x3?
A. Only the default constructor of object class
B. Only the no-argument constructor of class Z
C. Only the no-argument constructor of class Y
D. Only the default constructor of class X
正解：D

質問 8：
Given the code fragment:
StringBuilder sb = new StringBuilder ( ) ; Sb.append ("world");
Which code fragment prints Hello World?
A. sb.insert(0,"Hello "); System.out.println(sb);
B. sb.append(0,"Hello "); System.out.println(sb);
C. sb.set(0,"Hello "); System.out.println(sb);D
D. sb.add(0,"Hello "); System.out.println(sb);
正解：A
解説: (Topexam メンバーにのみ表示されます)