OCA - Practice Test 01

Duration 120 minutes,
Format: Multiple Choice
Number of Questions: 56
Passing Score: 65%

Questions from 43 to 56

import java.util.*;
public class ArrayTest {
public static void main(String[] args) {
List fishes = new ArrayList();
fishes.add("catfish");
fishes.add(1, "goldfish");
fishes.add(0, "clownfish");
fishes.add(1, "swordfish");
System.out.println(fishes);
}
}

What is the output?

Option a: [clownfish, swordfish, catfish, goldfish]
Option b: [clownfish, swordfish]
Option c: Generates a runtime error.
Option d: Generates a compile time error.

public class Demo {
public static void main(String[] args) {
InitializationExample init = new InitializationExample();
init.sum();
}
}
class InitializationExample {
private String name = "Integer";
{ System.out.println(name); }
private static int COUNT = 0;
static { System.out.println(COUNT); }
static { COUNT += 10; System.out.println(COUNT); }
public InitializationExample() {
System.out.println("constructor");
}
private void sum() {
COUNT++;
System.out.println(COUNT);
}
}

What is the output?

Option a: Prints output 0
10
Integer
constructor
Option b: Generates a runtime error.
Option c: Generates a compile time error.
Option d: Does nothing.

01. package demoPackage;
02. class Mammal {
03. public Mammal(int age) {
04. System.out.print("Mammal " + age);
05. }
06. }
07. public class Demo extends Mammal {
08. public Demo() {
09. System.out.print("Elephant");
10. }
11. public static void main(String[] args) {
12. new Mammal(5);
13. }
14. }

Option a: Elephant
Option b: Mammal
Option c: ElephantMammal
Option d: The code will not compile because of line 8.
Option e: The code will not compile because of line 11.

package demoPackage;

import java.io.*;
class OutOfTuneException extends Exception {
OutOfTuneException(String message) { super(message); }
}
public class Demo {
public void play() throws OutOfTuneException, FileNotFoundException {
throw new OutOfTuneException("Sour note!");
}
public static void main(String... keys) {
final Demo piano = new Demo();
try {
piano.play();
} catch (Exception e) {
System.out.println(e);
} finally {
System.out.println("Song finished!");
}
}
}

Which of the following could be a possible output?

Option a: Song finished!
Option b: An exception is printed: Sour note!
Option c: Both of the above.
Option d: None of the above.

// file Animal.java
public class Animal {
public int length = 2;
}
// file Jellyfish.java
public class Tiger extends Animal {
public int length = 5;
public static void main(String[] args) {
Tiger tiger = new Tiger();
Animal animal = new Tiger();
System.out.print(tiger.length);
System.out.print(animal.length);
}
}

What is the result?

Option a: Prints output: 52
Option b: Generates a run time error.
Option c: Generates a compile time error.
Option d: Prints output: 25
Option e: Does nothing.

Question 48.

Select the most appropriate answer.
In the following code, which is the earliest statement, where the object originally held in e, may be garbage collected:

1. public class demo {
2. public static void main (String args []) {
3. Employee e = new Employee("Bob", 48);
4. e.calculatePay();
5. System.out.println(e.printDetails());
6. e = null;
7. e = new Employee("Denise", 36);
7. e.calculatePay();
9. System.out.println(e.printDetails());
10. }
11. }

What is the output?

Option a: 1 2 3 4 5 6 7 8 9
Option b: 1 2 3 4 5 6 7 8 9 10
Option c: 1 2 3 4 5 6 7 8 9 10 11
Option d: The code will not compile because of line 6.
Option e: The code contains an infinite loop and does not terminate.

import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class BoolTest {
public static void main(String[] args) {
try {
String email= "test.rmail@golf.com";
Pattern p = Pattern.compile("^[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,6}$", Pattern.CASE_INSENSITIVE);
Matcher isEmailValid = p.matcher(email);
boolean emailValid = isEmailValid.find();
if (emailValid) {
System.out.println("Okay");
} else {
System.out.println("Not Okay");
}
} catch (Exception e) {
e.printStackTrace();
}
}
}

Option a: Prints: "Not Okay", in any case
Option b: Prints:"Okay", in any case
Option c: if the String email matches pattern, Prints: "Okay"
Option d: if the String email doesn’t match pattern, Prints: "Not Okay"
Option e: Generates a runtime error.
Option f: Generates a compile time error.

java.util.List values = new java.util.ArrayList();
values.add("Lisa");
values.add("Kevin");
values.add("Roger");
for(String value : values) {
System.out.print(value + ", ");
}

What is the output?

Option a: Lisa, Kevin, Roger,
Option b: Generates a runtime error.
Option c: Generates a compile time error.
Option d: Lisa, Roger, Kevin,
Option e: Kevin, Roger, Lisa,

public class BoolTest {
public static void main(String[] args) {
boolean x = false;
boolean y = false;
boolean z = x && y;
z = x || y;
z = !z;
System.out.println(!z);
}
}

What is the output?

Option a: true
Option b: false
Option c: Generates a compile time error.
Option d: Generates a runtime error.

What is the result?

Option a: Prints: “Java”
Option b: Prints: “Java Rules!”
Option c: Generates a compile time error.
Option d: Generates a runtime error.

class First {
{ System.out.println("1"); }
public void Top() { System.out.println("2"); }
public void Top(String s) { System.out.println("3"); }
}
class Second extends First {
{ System.out.println("4"); }
public Second() { System.out.println("5"); }
public Second(String s) { System.out.println("6"); }
}
public class Third extends Second {
{ System.out.println("7"); }
public void Bottom()
{ System.out.println("8"); }
public void Bottom(String s) { System.out.println("9"); }
public static void main(String[] args) { new Third(); }
}

What is the result?

Option a: 147
Option b: 1457
Option c: 369
Option d: 123456
Option e: 215478
Option f: 456821
Option g: 561243

10. class One {
11. public One foo() { return this; }
12. }
13. class Two extends One {
14. public One foo() { return this; }
15. }
16. class Three extends Two {
17. // insert method here
18. }

Which two methods, inserted individually, correctly complete the Three class?

Option a: public void foo() { }
Option b: public int foo() { return 3; }
Option c: public Two foo() { return this; }
Option d: public One foo() { return this; }
Option e: public Object foo() { return this; }