OCA

What is output by the following code? (Choose all that apply)
1: public class Fish {
2: public static void main(String[] args) {
3: int numFish = 4;
4: String fishType = "tuna";
5: String anotherFish = numFish + 1;
6: System.out.println(anotherFish + " " + fishType);
7: System.out.println(numFish + " " + 1);
8: } }

Which of the following are output by this code? (Choose all that apply)
3: String s = "Hello";
4: String t = new String(s);
5: if ("Hello".equals(s)) System.out.println("one");
6: if (t == s) System.out.println("two");
7: if (t.equals(s)) System.out.println("three");
8: if ("Hello" == s) System.out.println("four");
9: if ("Hello" == t) System.out.println("five");

Which are true statements? (Choose all that apply)

Given the code fragment:
// Line n1
switch (cardVal) {
case 4: case 5: case 6:
case 7: case 8:
System.out.println("Hit");
break;
case 9: case 10: case 11:
System.out.println("Double");
break;
case 15: case 16:
System.out.println("Surrender");
break;
default:
System.out.println("Stand");
}

Which two code fragments can be inserted at Line n1, independently, enable to print Stand?

Which of the following are valid Java identifiers? (Choose all that apply)

What is the output of the following program?
1: public class WaterBottle {
2: private String brand;
3: private boolean empty;
4: public static void main(String[] args) {
5: WaterBottle wb = new WaterBottle();
6: System.out.print("Empty = " + wb.empty);
7: System.out.print(", Brand = " + wb.brand);
8: } }

Which of the following are true? (Choose all that apply)
4: short numPets = 5;
5: int numGrains = 5.6;
6: String name = "Scruffy";
7: numPets.length();
8: numGrains.length();
9: name.length();

Which of the following Java operators can be used with boolean variables? (Choose all that
apply)

What data type (or types) will allow the following code snippet to compile? (Choose all that apply)
byte x = 5;
byte y = 10;
_____ z = x + y;

What is the output of the following application?
1: public class CompareValues {
2: public static void main(String[] args) {
3: int x = 0;
4: while(x++ < 10) {}
5: String message = x > 10 ? "Greater than" : false;
6: System.out.println(message+","+x);
7: }
8: }

What change would allow the following code snippet to compile? (Choose all that apply)
3: long x = 10;
4: int y = 2 * x;

What is the output of the following code snippet?
3: java.util.List<Integer> list = new java.util.ArrayList<Integer>();
4: list.add(10);
5: list.add(14);
6: for(int x : list) {
7: System.out.print(x + ", ");
8: break;
9: }

What is the output of the following code snippet?
3: int x = 4;
4: long y = x * 4 - x++;
5: if(y<10) System.out.println("Too Low");
6: else System.out.println("Just right");
7: else System.out.println("Too High");

What is the output of the following code?
1: public class TernaryTester {
2: public static void main(String[] args) {
3: int x = 5;
4: System.out.println(x > 2 ? x < 4 ? 10 : 8 : 7);
5: }}

What is the output of the following code snippet?
3: boolean x = true, z = true;
4: int y = 20;
5: x = (y != 10) ^ (z=false);
6: System.out.println(x+", "+y+", "+z);

How many times will the following code print "Hello World"?
3: for(int i=0; i<10 ; ) {
4: i = i++;
5: System.out.println("Hello World");
6: }

What is the output of the following code?
3: byte a = 40, b = 50;
4: byte sum = (byte) a + b;
5: System.out.println(sum);

What is the output of the following code?
1: public class ArithmeticSample {
2: public static void main(String[] args) {
3: int x = 5 * 4 % 3;
4: System.out.println(x);
5: }}

What is the output of the following code snippet?
3: int x = 0;
4: String s = null;
5: if(x == s) System.out.println("Success");
6: else System.out.println("Failure");

What is the output of the following code snippet?
3: int x1 = 50, x2 = 75;
4: boolean b = x1 >= x2;
5: if(b = true) System.out.println("Success");
6: else System.out.println("Failure");

What is the output of the following code snippet?
3: int c = 7;
4: int result = 4;
5: result += ++c;
6: System.out.println(result);

What is the output of the following code snippet?
3: int x = 1, y = 15;
4: while x < 10
5: y––;
6: x++;
7: System.out.println(x+", "+y);

What is the output of the following code snippet?
3: do {
4: int y = 1;
5: System.out.print(y++ + " ");
6: } while(y <= 10);

What is the output of the following code snippet?
3: boolean keepGoing = true;
4: int result = 15, i = 10;
5: do {
6: i--;
7: if(i==8) keepGoing = false;
8: result -= 2;
9: } while(keepGoing);
10: System.out.println(result);

What is the output of the following code snippet?
3: int count = 0;
4: ROW_LOOP: for(int row = 1; row <=3; row++)
5: for(int col = 1; col <=2 ; col++) {
6: if(row * col % 2 == 0) continue ROW_LOOP;
7: count++;
8: }
9: System.out.println(count);

What is the result of the following code snippet?
3: int m = 9, n = 1, x = 0;
4: while(m > n) {
5: m--;
6: n += 2;
7: x += m + n;
8: }
9: System.out.println(x);

What is the result of the following code snippet?
3: final char a = 'A', d = 'D';
4: char grade = 'B';
5: switch(grade) {
6: case a:
7: case 'B': System.out.print("great");
8: case 'C': System.out.print("good"); break;
9: case d:
10: case 'F': System.out.print("not good");
11: }

Which are the results of the following code? (Choose all that apply)
String letters = "abcdef";
System.out.println(letters.length());
System.out.println(letters.charAt(3));
System.out.println(letters.charAt(6));

Which are the results of the following code? (Choose all that apply)
String numbers = "012345678";
System.out.println(numbers.substring(1, 3));
System.out.println(numbers.substring(7, 7));
System.out.println(numbers.substring(7));

Which of the following can replace line 4 to print "avaJ"? (Choose all that apply)
3: StringBuilder puzzle = new StringBuilder("Java");
4: // INSERT CODE HERE
5: System.out.println(puzzle);

Which of these array declarations is not legal? (Choose all that apply)

Which of these compile when replacing line 8? (Choose all that apply)
7: char[]c = new char[2];
8: // INSERT CODE HERE

Which of these compile when replacing line 8? (Choose all that apply)
7: ArrayList l = new ArrayList();
8: // INSERT CODE HERE

Which of the following can fill in the blank in this code to make it compile? (Choose all
that apply)

public class Ant {
_____ void method() { }
}

Which of the following are true? (Choose all that apply)

Which of the following are true? (Choose all that apply)

Which of the following compile? (Choose all that apply)

Which of the following methods compile? (Choose all that apply)

Which of the following compile? (Choose all that apply)

Which of the following are true statements about the following code? (Choose all that
apply)
4: List<Integer> ages = new ArrayList<>();
5: ages.add(Integer.parseInt("5"));
6: ages.add(Integer.valueOf("6"));
7: ages.add(7);
8: ages.add(null);
9: for (int age : ages) System.out.print(age);

Which of the following can be inserted into the blank to create a date of June 21, 2014?
(Choose all that apply)
import java.time.*;
public class StartOfSummer {
public static void main(String[] args) {
LocalDate date = ____________________________
}
}

Given the following method, which of the method calls return 2? (Choose all that apply)
public int howMany(boolean b, boolean... b2) {
return b2.length;
}

Which of the following are true? (Choose all that apply)

Given the following my.school.ClassRoom and my.city.School class definitions, which line numbers in main() generate a compiler error? (Choose all that apply)

1: package my.school;
2: public class Classroom {
3: private int roomNumber;
4: protected String teacherName;
5: static int globalKey = 54321;
6: public int floor = 3;
7: Classroom(int r, String t) {
8: roomNumber = r;
9: teacherName = t; } }

1: package my.city;
2: import my.school.*;
3: public class School {
4: public static void main(String[] args) {
5: System.out.println(Classroom.globalKey);
6: Classroom room = new Classroom(101, ""Mrs. Anderson");
7: System.out.println(room.roomNumber);
8: System.out.println(room.floor);
9: System.out.println(room.teacherName); } }

Which of the following are true? (Choose all that apply)

Which are methods using JavaBeans naming conventions for accessors and mutators? (Choose all that apply)

What is the output of the following code?
1: package rope;
2: public class Rope {
3: public static int LENGTH = 5;
4: static {
5: LENGTH = 10;
6: } canSwim = b;}
7: public static void swing() {
8: System.out.print("swing ");
9: }
10:}
1: import rope.*;
2: import static rope.Rope.*;
3: public class Chimp {
4: public static void main(String[] args) {
5: Rope.swing();
6: new Rope().swing();
7: System.out.println(LENGTH);
8: }
9:}

Which are true of the following code? (Choose all that apply)
1: public class Rope {
2: public static void swing() {
3: System.out.print("swing ");
4: }
5: public void climb() {
6: System.out.println("climb ");
7: }
8: public static void play() {
9: swing();
10: climb();
11: }
12: public static void main(String[] args) {
13: Rope rope = new Rope();
14: rope.play();
15: Rope rope2 = null;
16: rope2.play();
17: }
18:}

What is the output of the following code?
import rope.*;
import static rope.Rope.*;
public class RopeSwing {
private static Rope rope1 = new Rope();
private static Rope rope2 = new Rope();
{
System.out.println(rope1.length);
}
public static void main(String[] args) {
rope1.length = 2;
rope2.length = 8;
System.out.println(rope1.length);
}
}

package rope;
public class Rope {
public static int length = 0;
}

How many compiler errors are in the following code?
1: public class RopeSwing {
2: private static final String leftRope;
3: private static final String rightRope;
4: private static final String bench;
5: private static final String name = "name";
6: static {
7: leftRope = "left";
8: rightRope = "right";
9: }
10: static {
11: name = "name";
12: rightRope = "right";
13: }
14: public static void main(String[] args) {
15: bench = "bench";
16: }
17:}

Which of the following can replace line 2 to make this code compile? (Choose
all that apply)
1: import java.util.*;
2: // INSERT CODE HERE
3: public class Imports {
4: public void method(ArrayList<String> list) {
5: sort(list);
6: }
7: }

What is the result of the following program?
1: public class Squares {
2: public static long square(int x) {
3: long y = x * (long) x;
4: x = -1;
5: return y;
6: }
7: public static void main(String[] args) {
8: int value = 9;
9: long result = square(value);
10: System.out.println(value);
11: } }

Which of the following are output by the following code? (Choose all that apply)
public class StringBuilders {
public static StringBuilder work(StringBuilder a, StringBuilder b) {
a = new StringBuilder("a");
b.append("b");
return a;
}
public static void main(String[] args) {
StringBuilder s1 = new StringBuilder("s1");
StringBuilder s2 = new StringBuilder("s2");
StringBuilder s3 = work(s1, s2);
System.out.println("s1 = " + s1);
System.out.println("s2 = " + s2);
System.out.println("s3 = " + s3);
}
}

Which of the following are true? (Choose 2)

Which of these classes compile and use a default constructor? (Choose all that apply)

Which code can be inserted to have the code print 2?
public class BirdSeed {
private int numberBags;
boolean call;
public BirdSeed() {
// LINE 1
call = false;
// LINE 2
}
public BirdSeed(int numberBags) {
this.numberBags = numberBags;
}
public static void main(String[] args) {
BirdSeed seed = new BirdSeed();
System.out.println(seed.numberBags);
} }

Which of the following complete the constructor so that this code prints out 50? (Choose all that apply)
public class Cheetah {
int numSpots;
public Cheetah(int numSpots) {
// INSERT CODE HERE
}
public static void main(String[] args) {
System.out.println(new Cheetah(50).numSpots);
}
}

What is the result of the following?
1: public class Order {
2: static String result = "";
3: { result += "c"; }
4: static
5: { result += "u"; }
6: { result += "r"; }
7: }
1: public class OrderDriver {
2: public static void main(String[] args) {
3: System.out.print(Order.result + " ");
4: System.out.print(Order.result + " ");
5: new Order();
6: new Order();
7: System.out.print(Order.result + " ");
8: }
9: }

What is the result of the following?
1: public class Order {
2: String value = "t";
3: { value += "a"; }
4: { value += "c"; }
5: public Order() {
6: value += "b";
7: }
8: public Order(String s) {
9: value += s;
10: }
11: public static void main(String[] args) {
12: Order order = new Order("f");
13: order = new Order();
14: System.out.println(order.value);
15: } }

Which of the following will compile when inserted in the following code? (Choose all that apply)
public class Order3 {
final String value1 = "1";
static String value2 = "2";
String value3 = "3";
{
// CODE SNIPPET 1
}
static {
// CODE SNIPPET 2
}
}

Which of the following are true about the following code? (Choose all that apply)
public class Create {
Create() {
System.out.print("1 ");
}
Create(int num) {
System.out.print("2 ");
}
Create(Integer num) {
System.out.print("3 ");
}
Create(Object num) {
System.out.print("4 ");
}
Create(int... nums) {
System.out.print("5 ");
}
public static void main(String[] args) {
new Create(100);
new Create(1000L);
}
}

What is the result of the following class?
1: import java.util.function.*;
2:
3: public class Panda {
4: int age;
5: public static void main(String[] args) {
6: Panda p1 = new Panda();
7: p1.age = 1;
8: check(p1, p -> p.age < 5);
9: }
10: private static void check(Panda panda, Predicate<Panda> pred) {
11: String result = pred.test(panda) ? "match" : "not match";
12: System.out.print(result);
13: } }

What is the result of the following code?
1: interface Climb {
2: boolean isTooHigh(int height, int limit);
3: }
4:
5: public class Climber {
6: public static void main(String[] args) {
7: check((h, l) -> h.append(l).isEmpty(), 5);
8: }
9: private static void check(Climb climb, int height) {
10: if (climb.isTooHigh(height, 10))
11: System.out.println("too high");
12: else
13: System.out.println("ok");
14: }
15:}

Which of the following lambda expressions can fill in the blank? (Choose all that apply)
List<String> list = new ArrayList<>();
list.removeIf(___________________);

Which lambda can replace the MySecret class to return the same value? (Choose all that apply)
interface Secret {
String magic(double d);
}
class MySecret implements Secret {
public String magic(double d) {
return "Poof";
}
}

Given the following class, which of the following is true? (Choose all that apply)
1: public class Snake {
2:
3: public void shed(boolean time) {
4:
5: if (time) {
6:
7: }
8: System.out.println(result);
9:
10: }
11: }

Given the following classes, which of the following can independently replace INSERT
IMPORTS HERE to make the code compile? (Choose all that apply)
package aquarium;
public class Tank { }
package aquarium.jellies;
public class Jelly { }
package visitor;
INSERT IMPORTS HERE
public class AquariumVisitor {
public void admire(Jelly jelly) { } }

Given the following classes, what is the maximum number of imports that can be removed
and have the code still compile?
package aquarium; public class Water { }
package aquarium;
import java.lang.*;
import java.lang.System;
import aquarium.Water;
import aquarium.*;
public class Tank {
public void print(Water water) {
System.out.println(water); } }

Given the following classes, which of the following snippets can be inserted in place of
INSERT IMPORTS HERE and have the code compile? (Choose all that apply)
package aquarium;
public class Water {
boolean salty = false;
}
package aquarium.jellies;
public class Water {
boolean salty = true;
}
package employee;
INSERT IMPORTS HERE
public class WaterFiller {
Water water;
}

Given the following class, which of the following calls print out Blue Jay? (Choose all that
apply)
public class BirdDisplay {
public static void main(String[] name) {
System.out.println(name[1]);
} }

Which of the following legally fill in the blank so you can run the main() method from the
command line? (Choose all that apply)
public static void main( )

Which of the following are legal entry point methods that can be run from the command
line? (Choose all that apply)

Which of the following are true? (Choose all that apply)

Which of the following are true? (Choose all that apply)

Which of the following are true? (Choose all that apply)

Given the following class in the file /my/directory/named/A/Bird.java:
INSERT CODE HERE
public class Bird { }
Which of the following replaces INSERT CODE HERE if we compile from /my/directory?
(Choose all that apply)

Which of the following lines of code compile? (Choose all that apply)

Given the following class, which of the following lines of code can replace INSERT CODE
HERE to make the code compile? (Choose all that apply)
public class Price {
public void admission() {
INSERT CODE HERE
System.out.println(amount);
} }

Which of the following are true? (Choose all that apply)
public class Bunny {
public static void main(String[] args) {
Bunny bun = new Bunny();
} }

Which represent the order in which the following statements can be assembled into a program
that will compile successfully? (Choose all that apply)
A: class Rabbit {}
B: import java.util.*;
C: package animals;

Suppose we have a class named Rabbit. Which of the following statements are true?
(Choose all that apply)
1: public class Rabbit {
2: public static void main(String[] args) {
3: Rabbit one = new Rabbit();
4: Rabbit two = new Rabbit();
5: Rabbit three = one;
6: one = null;
7: Rabbit four = one;
8: three = null;
9: two = null;
10: two = new Rabbit();
11: System.gc();
12: } }

What is true about the following code? (Choose all that apply)
public class Bear {
protected void finalize() {
System.out.println("Roar!");
}
Review Questions 49
c01.indd 1½ 4/2014 Page 49
public static void main(String[] args) {
Bear bear = new Bear();
bear = null;
System.gc();
} }

What does the following code output?
1: public class Salmon {
2: int count;
3: public void Salmon() {
4: count = 4;
5: }
6: public static void main(String[] args) {
7: Salmon s = new Salmon();
8: System.out.println(s.count);
9: } }

22. Which of the following are true statements? (Choose all that apply)

Which of the following are true? (Choose all that apply)

Which of the following statements can be inserted in the blank line so that the code will
compile successfully? (Choose all that apply)
public interface CanHop {}
public class Frog implements CanHop {
public static void main(String[] args) {
frog = new TurtleFrog();
}
}
public class BrazilianHornedFrog extends Frog {}
public class TurtleFrog extends Frog {}

Which statement(s) are correct about the following code? (Choose all that apply)
public class Rodent {
protected static Integer chew() throws Exception {
System.out.println("Rodent is chewing");
return 1;
}
}
public class Beaver extends Rodent {
public Number chew() throws RuntimeException {
System.out.println("Beaver is chewing on wood");
return 2;
}
}

Which of the following may only be hidden and not overridden? (Choose all that apply)

Which of the following statements about polymorphism are true? (Choose all that apply)

Which statements are true for both abstract classes and interfaces? (Choose all that apply)

What modifiers are assumed for all interface variables? (Choose all that apply)