Java Developer - Common Jobs

Welcome to your Java Developer

Java

Which company originally developed Java?

Microsoft

IBM

Sun Microsystems

Oracle

Java

Which of these is not a Java keyword?

Boolean

void

static

public

Java

What is the file extension of compiled Java classes?

.java

.class

.jar

.exe

Java

Which package is imported by default in every Java program?

java.io

java.lang

java.net

java.util

Java

Which keyword is used to inherit a class?

inherits

implements

extends

override

Java

Which keyword is used to create an object in Java?

create

object

new

make

Java

What is the parent class of all classes in Java?

Class

Runtime

Object

System

Java

Which of these allows multiple methods with the same name but different parameters?

Overriding

Inheritance

Encapsulation

Overloading

Java

Which collection class allows key-value pairs and does not allow duplicate keys?

Set

Queue

List

Map

Java

Which interface is implemented by all collection classes in Java?

Collection

Iterable

List

Set

Java

Which of the following is a marker interface?

Runnable

Comparable

Serializable

Cloneable

Java

What is the main advantage of using streams in Java 8?

Easier syntax

Works only on arrays

Supports functional programming and parallel operations

Replaces threads

Java

Which feature of Java 8 allows methods in interfaces to have a body?

Anonymous classes

Static methods

Lambda expressions

Default methods

Java

Which keyword is used to handle exceptions in Java?

try-catch

exception

error

handle

Java

Which garbage collection algorithm is used in the JVM by default (Java 11+)

CMS

G1 GC (Garbage First)

Parallel GC

Serial GC

Java

What is the difference between == and .equals()?

== compares references, .equals() compares values

No difference

Both compare object content

== compares values, .equals() compares references

Java

Which Java keyword is used to define an enumeration?

Enum

enum

enumeration

define

Java

What is the purpose of the volatile keyword in Java?

Ensures visibility of changes across threads

Makes variable thread-local

Used for immutability

Makes a variable constant

Java

Which design pattern is used to ensure only one instance of a class exists?

Observer Pattern

Factory Pattern

Builder Pattern

Singleton Pattern

Java

What does the transient keyword do?

Excludes a field from serialization

Converts object to string

Makes variable synchronized

Marks a variable as temporary

Java

What is the purpose of the static keyword?

Create dynamic objects

Allocate memory only once for a class member

Automatically call garbage collector

Make method thread-safe

Java

Which collection maintains insertion order?

LinkedHashSet

HashSet

TreeSet

PriorityQueue

Java

Which exception is thrown when an array is accessed out of its bounds?

NullPointerException

ArrayIndexOutOfBoundsException

IndexException

ArrayOverflowException

Java

Which keyword prevents a method from being overridden?

final

abstract

static

private

Java

What does the transient keyword do?

Converts object to string

Marks a variable as temporary

Makes variable synchronized

Excludes a field from serialization