Java Foundation Test 3 Code 819

Welcome to your Foundation Java Test - 3

Name

Phone

Question: Which of the following statements are true?

Select 2 option(s)

Private methods cannot be overridden in subclasses.

A subclass can override any method in a non-final superclass.

An overriding method can declare that it throws a wider spectrum of checked exceptions than the method it is overriding.

The parameter list of an overriding method must be a subset of the parameter list of the method that it is overriding.

The overriding method may opt not to declare any throws clause even if the original method has a throws clause.

Question: Which of the following statements are true?

Select 2 option(s)

Package member classes can be declared static.

Classes declared as members of top-level classes can be declared static.

Local classes can be declared static.

Anonymous classes cannot be declared static.

No type of class can be declared static.

Question: You have created several threads in your application. To ensure that important tasks are performed quickly, you have increased the priority of some threads and lowered the priority of others. At run time, however, you observe that the lower priority threads rarely get a chance to run.

What is this problem called?

Select 1 option(s)

Deadlock

Livelock

Thrashing

Starvation

None

Question: Given:

class Triangle{
public int base;
public int height;
public double area = 0;

public Triangle(int pBase, int pHeight){
this.base = pBase; this.height = pHeight;
updateArea();
}
public void updateArea(){
double a = base*height/2;
area = a;
}
public void setBase(int b){ base = b; updateArea(); }
public void setHeight(int h){ height = h; updateArea(); }
}

Which variables are not accessible from anywhere within given class code except from the scope in which they are declared?

Select 1 option(s)

base, height, area

area, b, h

base, height

b, h, a

None

Question: Java Module system achieves which of the following objectives for a Java project?

Select 3 option(s)

It encapsulates the project.

It encapsulates the packages.

It provides a central repository for keeping classes.

It enables a project to manage multiple versions of dependencies.

It provides a reliable mechanism to let components of an application specify their dependencies on each other.

It provides a way to specify services and declare dependence on such services.

Question: How many methods have to be provided by a class that is not abstract and that says it implements Serializable interface?

Select 1 option(s)

None

Question: Identify correct statements about the Java module system.

Select 2 option(s)

If a request is made from an automatic module to load a type whose package is not defined in any known module then the module system will attempt to load it from the classpath.

The unnamed module can only access types present in the unnamed module.

Code from a named module can access classes that are on the classpath.

If a package is defined in both a named module and the unnamed module then the package in the unnamed module is ignored.

An automatic module cannot access classes from the unnamed module.

Question: Select the correct order of restrictiveness for access modifiers...

(First one should be least restrictive)

Select 1 option(s)

public < protected < package (i.e. no modifier) < private

public < package (i.e. no modifier) < protected < private

public < protected < private < package (i.e. no modifier)

protected < package (i.e. no modifier) < private < public

depends on the implementation of the class or method.

None

Question: Which of the following statements about an array are correct?

Select 2 option(s)

An array can dynamically grow in size.

Arrays can be created only for primitive types.

Every array has a built in property named 'size' which tells you the number of elements in the array.

Every array has an implicit method named 'length' which tells you the number of elements in the array.

Element indexing starts at 0.

All arrays can be cloned using clone method.

10.

Question: In Java, Strings are immutable. A direct implication of this is...

Select 2 option(s)

You cannot call methods like "1234".replace('1', '9'); and expect to change the original String.

You cannot change a String object, once it is created.

You can change a String object only by the means of its methods.

You cannot extend String class.

You cannot compare String objects.

11.

Question: Which of the following statements are correct regarding abstract classes and interfaces?

Select 2 option(s)

An abstract class can have private as well as static methods while an interface can not have static methods.

An abstract class cannot implement multiple interfaces while an interface can extend multiple interfaces.

Abstract classes can have abstract methods but interface cannot.

Abstract classes can have instance fields but interfaces can't.

An abstract class can have final methods but an interface cannot.

12.

Question: Under what situations does a class get a default constructor?

Select 1 option(s)

All classes in Java get a default constructor.

You have to define at least one constructor to get the default constructor.

If the class does not define any constructors explicitly.

All classes get default constructor from Object class.

None of the above.

None

13.

Question: Objects of which of the following classes can be thrown using a throw statement?

Select 3 option(s)

Event

Object

Throwable

Exception

RuntimeException

14.

Question: Which method must be implemented by a class implementing the Callable interface?

Select 1 option(s)

run()

execute()

call()

do()

None

15.

Question: Which variables declared in the encapsulating class or in the method, can an inner class access if the inner class is defined in a static method of encapsulating class?

Select 2 option(s)

All static variables.

All final instance variables.

All instance variables.

All automatic variables.

All final or effectively final static or automatic variables.

16.

Question: Given the following definition of class, which member variables are accessible from OUTSIDE the package com.enthu.qb?

package com.enthu.qb;
public class TestClass{
int i;
public int j;
protected int k;
private int l;
}

Select 2 option(s)

Member variable i.

Member variable j.

Member variable k.

Member variable k, but only for subclasses.

Member variable l.

17.

Question: Which of the following are benefits of polymorphism?

Select 2 option(s)

It makes the code more reusable.

It makes the code more efficient.

It protects the code by preventing extension.

It makes the code more dynamic.

18.

Question: What will be the output of the following program (excluding the quotes)?

public class SubstringTest{
public static void main(String args[]){
String String = "string isa string";
System.out.println(String.substring(3, 6));
}
}

Select 1 option(s)

It will not compile.

"ing is"

"ing isa"

"ing " (There is a space after g)

None of the above.

None

19.

Question: In which of these variable declarations, will the variable remain uninitialized unless explicitly initialized?

Select 1 option(s)

Declaration of an instance variable of type int.

Declaration of a static class variable of type float.

Declaration of a local variable of type float.

Declaration of a static class variable of class Object.

Declaration of an instance variable of class Object.

None

20.

Question: You have a collection (say, an ArrayList) which is read by multiple reader threads and which is modified by a single writer thread. The collection allows multiple concurrent reads but does not tolerate concurrent read and write. Which of the following strategies will you use to obtain best performance?

Select 1 option(s)

Synchronize all access to the collection.

Make the collection variable final.

Make the collection variable final and volatile.

Wrap the collection into its synchronized version using Collections.synchronizedCollection().

Encapsulate the collection into another class and use ReadWriteLock to manage read and write access.

None

21.

Question: Identify correct statements about annotations.

Select 1 option(s)

@SuppressWarnings can be used only on a class, constructor, or a method.

@Override can only be used on instance methods.

@SafeVarargs can only be used on methods.

@Deprecated can be used only on a class, constructor, or a method.

@SuppressWarnings("all") can be used suppress all warnings from a method or a class.

None

22.

Question: Which of the following are valid?

Select 2 option(s)

23.

Question: Which of these interfaces are in the Java Collections framework?

Select 4 option(s)

Set

Union

BitSet

Collection

Map

NavigableMap

24.

Question: Which of the following methods are available in java.util.concurrent.ConcurrentMap in addition to the methods provided by java.util.Map?

Select 1 option(s)

boolean remove(Object key, Object value)

boolean remove(Object key)

V putIfAbsent(K key, V value)

Object removeIfPresent(Object key)

boolean replace(K key, V oldValue, V newValue)

None of the above.

None

25.

Question: In the following code what will be the output if 0 (integer value zero) is passed to loopTest()?

public class TestClass{
public void loopTest(int x){
loop: for (var i = 1; i < 5; i++){
for (var j = 1; j < 5; j++){
System.out.println(i);
if (x == 0) { continue loop; }
System.out.println(j);
}
}
}
}

Select 1 option(s)

The program will not compile.

It will print 1 2 3 4.

It will print 1 1 2 3 4.

It will print 1 1 2 2 3 3 4 4.

Produces no output.

None

26.

Question: An abstract method cannot be overridden.

Select 1 option(s)

True

False

None

27.

Question: Which of the following are meta-annotations?

Select 3 option(s)

@Repeatable

@Retention

@SafeVarargs

@Target

@FunctionalInterface

28.

Question: Which is/are the root interface(s) for all collection related interfaces?

Select 2 option(s)

BaseCollection

Collection

List

Set

Map

29.

Question: Using a break in a while loop causes the loop to break the current iteration and start the next iteration of the loop.

Select 1 option(s)

True

False

None

30.

Question: Which of the following are valid standard country locale codes as returned by getCountry() method of Locale?

Select 3 option(s)

utf

UTF8

31.

Question: Which of these statements concerning the use of collection interfaces of the Java standard class library are true?

Select 1 option(s)

None of the standard collection classes are thread safe.

Class HashSet implements SortedSet.

Collection classes implementing List cannot have duplicate elements.

ArrayList can only accommodate a fixed number of elements.

Some operations may throw an UnsupportedOperationException.

None

32.

Question: Which of the following statements are true?

Select 2 option(s)

Private keyword can never be applied to a class.

Synchronized keyword can never be applied to a class.

Synchronized keyword may be applied to a non-primitive variable.

Final keyword can never be applied to a class.

A final variable can be hidden in a subclass.

33.

Question: What can be the type of a catch argument?

(Select the best option.)

Select 1 option(s)

Any class that extends java.lang.Exception.

Any class that extends java.lang.Exception except any class that extends java.lang.RuntimeException.

Any class that is-a Throwable.

Any Object.

Any class that extends Error.

None

34.

Question: Which of the following operators can be used in conjunction with a String object?

Select 3 option(s)

35.

Question: Identify legal module names.

Select 3 option(s)

com.amazing.movie-rentals

com.amazing.movierentals

amazing-movierentals

com.amazing.$movierentals

no1movierentals

com.amazing.1movierentals

36.

Question: Which of these statements about interfaces are true?

Select 4 option(s)

Interfaces are always abstract.

An interface can have static methods.

All methods in an interface are abstract although you need not declare them to be so.

Fields of an interface may be declared as transient or volatile but not synchronized.

Interfaces cannot be final.

Interfaces allow multiple implementation inheritance through default methods.

37.

Question: A JDBC driver implementation must provide implementation classes for which of the following interfaces?

Select 3 option(s)

java.sql.DriverManager

java.sql.Driver

java.sql.Connection

java.sql.Statement

java.sql.SQLException

java.sql.Date

38.

Question: Which of the following statements is/are true?

Select 1 option(s)

Subclasses must define all the abstract methods that the superclass defines.

A class implementing an interface must define all the methods of that interface.

A class cannot override the super class's constructor.

It is possible for two classes to be the superclass of each other.

An interface can implement multiple interfaces.

None

39.

Question: What is the correct declaration for an abstract method 'add' in a class that is accessible to any class, takes no arguments and returns nothing?

Select 1 option(s)

public void add();

abstract add();

abstract null add();

abstract public void add(){ }

abstract public void add() throws Exception;

None

40.

Question: Which of the following is not a primitive data value in Java?

Select 2 option(s)

"x"

'x'

10.2F

Object

false

41.

Question: Which of the following statements are correct?

Select 3 option(s)

An abstract class can be extended by an abstract or a concrete class.

A concrete class can be extended by an abstract or a concrete class.

An interface can be extended by another interface.

An interface can be extended by an abstract class.

An interface can be extended by a concrete class.

An abstract class cannot implement an interface.

42.

Question: An overriding method must have a same parameter list and the same return type as that of the overridden method.

Select 1 option(s)

True

False

None

43.

Question: Which of the following code fragments can you use to get a JDBC connection?

Select 1 option(s)

Properties p = new Properties();
p.setProperty("user", userid);
p.setProperty("password", pwd);
DriverManager.setClientInfo(p);
Connection c = DriverManager.getConnection(url);

Properties p = new Properties();
p.setProperty("user", userid);
p.setProperty("password", pwd);
Connection c = DriverManager.getConnection(dburl);
c.setClientInfo(p);
c.connect();

Properties p = new Properties();
p.setProperty("user", userid);
p.setProperty("password", pwd);
Connection c = DriverManager.getConnection(dburl, p);

Connection c = DriverManager.getConnection(url);
c.connect(userid, pwd)

None

44.

Question: Given:

//In file AccessTest.java
package a;
public class AccessTest {
int a;
private int b;
protected void c(){ }
public int d(){ return 0; }
}

//In file AccessTester.java
package b;
import a.AccessTest;

public class AccessTester extends AccessTest{
public static void main(String[] args) {
AccessTest ref = new AccessTest();

}
}

Idenfity the correct statements -

Select 1 option(s)

Only c() and d() can be accessed by ref.

b, c(), as well as d(), can be accessed by ref.

Only d() can be accessed by ref.

Only a and d() can be accessed by ref.

None

45.

Question: Consider the following code:

Locale myLoc = new Locale("fr", "FR");
ResourceBundle rb = ResourceBundle.getBundle("appmessages", myLoc);
//INSERT CODE HERE

Which of the following lines of code will assign a ResourceBundle for a different Locale to rb than the one currently assigned?

Select 2 option(s)

rb = ResourceBundle.getBundle("appmessages", new Locale("ch", "CH"));

rb = ResourceBundle.getBundle("appmessages", CHINA);

myLoc.setLocale(Locale.CHINA);

myLoc.setLocale(new Locale("ch", "CH"));

rb = ResourceBundle.getBundle("appmessages", Locale.CHINA);

rb.setLocale(Locale.CHINA);

46.

Question: Which of these statements are true?

Select 2 option(s)

A static method can call other non-static methods in the same class by using the 'this' keyword.

A class may contain both static and non-static variables and both static and non-static methods.

Each object of a class has its own copy of each non-static member variable.

Instance methods may access local variables of static methods.

All methods in a class are implicitly passed a 'this' parameter when called.

47.

Question: What classes can a non-static nested class extend?

(Provided that the class to be extended is visible and is not final.)

Select 1 option(s)

Only the encapsulating class.

Any top level class.

Any class.

It depends on whether the inner class is defined in a method or not.

None of the above.

None

48.

Question: Consider the following method:

public void myMethod(int m, Object p, double d){
... valid code here
}

Assuming that there is no other method with the same name, which of the following options are correct regarding the above method?

Select 1 option(s)

If this method is called with two parameters, the value of d in the method will be 0.0.

If this method is called with one parameter, the value of p and d in the method will be null and 0.0 respectively.

If this method is called with one parameter, the call will throw a NullPointerException.

If this method is called with one parameter, the call will throw a NullPointerException only if the code in the method tries to access p.

If this method is called with two parameters, the code will not compile.

None

49.

Question: Which operators will always evaluate all the operands?

Select 2 option(s)

50.

Question: Which of the following interfaces can be used to execute a stored procedure on the database?

Select 1 option(s)

CallableStatement

PreparedStatement

ProceduralStatement

StoredStatement

None

51.

Question: Consider the following code:

public class Conversion{
public static void main(String[] args){
int i = 1234567890;
float f = i;
System.out.println(i - (int)f);
}
}

What will it print when run?

Select 1 option(s)

It will print 0.

It will not print 0.

It will not compile.

It will throw an exception at runtime.

None of the above.

None

52.

Question: Which of the following are valid operators in Java?

Select 4 option(s)

53.

Question: Which of the following are standard annotations used to suppress various warnings generated by the compiler?

Select 3 option(s)

@SuppressWarnings("rawtypes")

@SuppressWarnings({"deprecation", "unchecked"})

@SuppressWarnings("deprecation", "unchecked")

@SafeVarargs

@Override

@Deprecated

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