Java platform and JVM overview - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the Java Virtual Machine (JVM)?

The JVM is a program that runs Java bytecode on any device or operating system, making Java programs portable and platform-independent.

beginner

What are the main components of the Java platform?

The Java platform includes the Java Development Kit (JDK), Java Runtime Environment (JRE), and the Java Virtual Machine (JVM).

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How does Java achieve platform independence?

Java code is compiled into bytecode, which the JVM interprets or compiles on the target machine, allowing the same code to run anywhere with a compatible JVM.

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What is bytecode in Java?

Bytecode is an intermediate, platform-neutral code generated by the Java compiler. The JVM executes this bytecode on any platform.

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What is the difference between JDK and JRE?

JDK (Java Development Kit) includes tools to develop Java programs, including the compiler. JRE (Java Runtime Environment) includes the JVM and libraries to run Java programs.

What does JVM stand for?

A Java Version Manager

B Java Variable Method

C Java Visual Model

D Java Virtual Machine

JVM stands for Java Virtual Machine, which runs Java bytecode.

Which component compiles Java source code into bytecode?

A JVM

B JRE

C JDK

D Java API

The JDK includes the Java compiler that converts source code into bytecode.

What is bytecode?

A Intermediate code executed by JVM

B Source code written by the programmer

C Machine code for a specific CPU

D A type of Java library

Bytecode is an intermediate code that JVM executes, enabling platform independence.

Which part of the Java platform is responsible for running Java programs?

A JRE

B JVM

C JDK

D Java API

The JVM runs Java bytecode and executes Java programs.

What makes Java programs platform-independent?

A Java bytecode and JVM

B Java API libraries

C Operating system compatibility

D Java source code

Java bytecode runs on any JVM, which exists for many platforms, making Java programs platform-independent.

Explain how the Java platform enables a program to run on different operating systems without changes.

Think about what happens after you write Java code and before it runs.

Describe the roles of JDK, JRE, and JVM in the Java platform.

Consider which part you use to write code and which part runs it.