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WorksheetsJava SE: Programming I
Total questions: 10
Worksheet time: 7mins
Given the code fragment:
public class ForTest {
public static void main(String[] args) { int[] array = {1, 2, 3};
for ( foo ) {
}
}
Which three code fragments, when replaced individually for foo, enables the program to
compile?
A. int i : array
B. int i = 0; i < 1;
C. ; ;
D. ; i < 1; i++
E. i = 0; i<1;
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 x field
B. The y field
C. The sum field
D. The setX ( ) method
E. The setY ( ) method
A. 100210
B. Compilation fails due to an error in line n1
C. Compilation fails due to an error at line n2
D. Compilation fails due to an error at line n3
Which two statements are true?
A. An abstract class can implement an interface.
B. An abstract class can be extended by an interface.
C. An interface CANNOT be extended by another interface.
D. An interface can be extended by an abstract class.
E. An abstract class can be extended by a concrete class.
Given:
abstract class A1 {
public abstract void m1();
public void m2() { System.out.println("Green"); }
}
abstract class A2 extends A1 { public abstract void m3();
public void m1() { System.out.println("Cyan"); } public void m2()
{
System.out.println("Blue"); }
}
public class A3 extends A2 {
public void m1() { System.out.println("Yellow"); } public void m2()
{ System.out.println("Pink"); } public void m3() { System.out.println("Red"); }
public static void main(String[] args) {
A2 tp = new A3(); tp.m1();
tp.m2();
tp.m3();
}
}
What is the result?
A. Yellow Pink Red
B. Cyan Blue Red C.
C.Cyan Green Red D.
D.Compilation Fails
A. hEllOjAvA!
B. Hello java!
C. Out of limits hEllOjAvA!
D. Out of limits
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
public class ForTest {
public static void main(String[] args) { int[] arrar = {1,2,3};
for ( foo ) {
}
}
}
Which three are valid replacements for foo so that the program will compiled and run?
A. int i: array
B. int i = 0; i < 1; i++
C. ;;
D. ; i < 1; i++
E. ; i < 1;
You are writing a method that is declared not to return a value. Which two are permitted in
the method body?
A. omission of the return statement
B. return null;
C. return void;
D. return;
A. asc = sc;
B. sc = asc;
C. asc = (object) sc;
D. asc = sc.clone ()
