Java SE: Programming I

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 ()