Java Introduction to Java Exercises

Which of the following statements about Java is correct?

Java is a low-level programming language.

Java is platform-independent due to the Java Virtual Machine (JVM).

Java code can only run on Windows operating system.

Java does not support object-oriented programming.

Java is a high-level, object-oriented programming language. Its key feature is platform independence, achieved through the Java Virtual Machine (JVM), which allows Java programs to run on any system without modification.

Option 1 is wrong because Java is high-level.
Option 3 is wrong because Java runs on multiple platforms (Windows, Linux, macOS).
Option 4 is wrong because Java fully supports object-oriented programming concepts like classes, objects, inheritance, and polymorphism.

Who is the creator of the Java programming language?

Dennis Ritchie

James Gosling

Bjarne Stroustrup

Guido van Rossum

Java was developed by James Gosling at Sun Microsystems in 1995. It was designed to be a simple, object-oriented, and platform-independent language.

Option 1 (Dennis Ritchie) created C.
Option 3 (Bjarne Stroustrup) created C++.
Option 4 (Guido van Rossum) created Python.

Which of the following is not a feature of Java?

Platform independence

Object-oriented

Use of pointers

Robust and secure

Java does not support pointers explicitly, unlike languages like C or C++. This design choice enhances security and robustness.

Option 1 is a key feature: Java programs can run on any platform using JVM.
Option 2 is true: Java is fully object-oriented.
Option 4 is true: Java emphasizes reliability and security with strong memory management and exception handling.

Which of the following is the correct definition of Java Virtual Machine (JVM)?

A hardware processor for running Java programs

A compiler that only compiles Java source code

An editor used to write Java programs

Software that converts Java bytecode into machine code and runs it

The Java Virtual Machine (JVM) is a software engine that executes Java bytecode on any platform, making Java platform-independent.

Option 1 is incorrect: JVM is not hardware.
Option 3 is incorrect: JVM is not an editor.
Option 2 is incorrect: JVM runs bytecode; the compiler (javac) generates bytecode from source code.

Java was originally developed for which type of devices?

Embedded devices and consumer electronics

Desktop applications only

Web servers only

Mobile apps only

Java was originally developed by Sun Microsystems in the early 1990s for embedded devices and consumer electronics, such as set-top boxes and smart appliances. Its platform independence and portability made it ideal for a wide range of devices.

Option 2 is incorrect: Java was not limited to desktop applications.
Option 3 is incorrect: While Java can run on servers, that was not its original target.
Option 4 is incorrect: Mobile app development came later with Java ME and Android.

Which of the following best describes “Write Once, Run Anywhere” (WORA) in Java?

Java code can be written once and run on any platform with JVM

Java programs need to be rewritten for each operating system

Java can only run on Windows computers

Java code automatically converts into machine code for every platform

“Write Once, Run Anywhere (WORA)” is a key principle of Java. It means that Java programs, once compiled into bytecode, can run on any platform that has a Java Virtual Machine (JVM). This makes Java highly portable.

Option 2 is incorrect: Java does not require rewriting for different OS.
Option 3 is incorrect: Java runs on multiple operating systems.
Option 4 is misleading: JVM interprets or just-in-time compiles bytecode; the code itself does not auto-convert.

Which component of the Java platform is responsible for converting bytecode into machine code at runtime?

Java Compiler (javac)

Java Development Kit (JDK)

Java Runtime Environment (JRE)

Just-In-Time (JIT) Compiler

The Just-In-Time (JIT) Compiler, a part of the JVM, converts Java bytecode into native machine code at runtime for better performance.

Option 1 is incorrect: javac compiles Java source code into bytecode, not machine code.
Option 2 is incorrect: JDK provides tools to develop Java programs but doesn’t execute them.
Option 3 is incorrect: JRE provides the environment (libraries + JVM) but doesn’t directly perform compilation.
Option 4 is correct: JIT compiles bytecode to machine code on the fly.

Which of the following statements about Java is true?

Java is platform-dependent and cannot run on multiple OS

Java supports multiple inheritance through classes

Java programs are executed by the Java Virtual Machine (JVM)

Java does not support multithreading

Java programs are compiled into bytecode, which is executed by the Java Virtual Machine (JVM). This allows Java programs to run on any platform with a JVM, making it platform-independent.

Option 1 is incorrect: Java is platform-independent.
Option 2 is incorrect: Java does not support multiple inheritance with classes; it uses interfaces.
Option 4 is incorrect: Java supports multithreading.
Option 3 is correct: JVM executes bytecode and ensures platform independence.

Which of the following is true about Java bytecode?

Bytecode is written directly by the programmer

Bytecode can run without JVM on any machine

Bytecode is platform-independent and executed by the JVM

Bytecode is the same as machine code

Java bytecode is the intermediate code generated after compiling Java source code. It is platform-independent and requires the JVM to execute. This is what makes Java programs portable across different operating systems.

Option 1 is incorrect: Programmers write source code, not bytecode.
Option 2 is incorrect: Bytecode cannot run directly on a machine; it needs JVM.
Option 4 is incorrect: Bytecode is not machine code; it’s an intermediate representation.
Option 3 is correct: Bytecode runs on any platform with JVM.

Why is Java considered more secure compared to languages like C or C++?

Java allows direct memory manipulation using pointers

Java programs are executed as machine code directly

Java runs inside the JVM, preventing unauthorized access and memory corruption

Java does not support object-oriented programming

Java is more secure because it runs inside the Java Virtual Machine (JVM), which provides a sandbox environment. This prevents unauthorized access, memory corruption, and unsafe operations like direct pointer manipulation.

Option 1 is incorrect: Java does not allow pointers, unlike C/C++.
Option 2 is incorrect: Java bytecode is executed by JVM, not directly as machine code.
Option 4 is incorrect: Java fully supports object-oriented programming.
Option 3 is correct: JVM ensures security and controlled execution of Java programs.

About This Exercise: Java – Introduction

Welcome to the Java Introduction exercises — the ideal starting point for anyone new to programming or looking to build a solid foundation in Java. Whether you are a complete beginner or revisiting the basics, this set of Java exercises is carefully designed to help you understand the fundamental concepts that are essential before moving on to more advanced Java topics.

Java is a versatile and widely-used programming language known for its platform independence, object-oriented nature, and robustness. In this section, you will learn the core building blocks of Java: syntax, variables, data types, operators, input/output, and control flow statements such as if-else and loops. Mastering these basics is crucial for writing clean, efficient, and error-free Java programs.

Each exercise in the Introduction to Java series is crafted to provide hands-on experience and practical understanding. From learning basic syntax to solving beginner-level programming challenges, these exercises will help you build confidence in Java coding. The problems are suitable for school and college students, coding bootcamp learners, and self-taught developers aiming to strengthen their Java fundamentals.

In addition to multiple choice questions (MCQs) and coding exercises, we provide detailed explanations for every answer. This approach ensures that you not only get the right solution but also understand the reasoning behind it. By practicing regularly, you will develop a strong grasp of Java syntax, control structures, and variable handling, which forms the foundation for learning advanced topics like classes, objects, inheritance, and exception handling.

This Java Introduction section is also highly beneficial for those preparing for coding interviews, academic exams, or certification tests. The exercises are structured with gradually increasing difficulty, allowing you to learn at your own pace. Once you complete the Introduction exercises, you can explore other Java topics on SolutionBazz such as Object-Oriented Programming, Data Structures, File Handling, and Java Collections to expand your programming skill set.

Consistency is key in learning Java. These exercises are designed to help you develop the right problem-solving mindset and coding habits necessary for a successful programming journey. Whether your goal is to become a software developer, Android app developer, backend engineer, or just someone passionate about coding, mastering Java basics is your first and most important step.

Start practicing the Introduction to Java exercises today, and build your Java skills one concept at a time. With regular practice and a curious mindset, you will soon be comfortable writing your own Java programs and tackling more advanced programming challenges with confidence.