Writing My First Java Program

JDK Tutorials - Herong's Tutorial Examples

∟Writing My First Java Program

This section provides a tutorial example on how to write, compile, and execute the first Java program with JDK 1.8.0.

When JDK is installed on your machine, it provides two commands for you to compile and run Java programs.

"javac class_name.java" - Compiles a Java program stored a file named with the program class name.
"java -classpath . class_name" - Runs a compiled Java program. "-classpath ." specifies the current directory as the class path.

Let's try these commands with a very simple Java program. Use NotePad to enter the following Java program into a file called Hello.java:

class Hello {
   public static void main(String[] a) {
      System.out.println("Hello world!");
   }
}

Then compile this program in a command window with the "javac" command:

herong> \progra~1\java\jdk-17.0.1\bin\javac Hello.java

To execute the program, use the java command:

herong> \progra~1\java\jdk-17.0.1\bin\java Hello

Hello world!

Congratulations, you have successfully entered, compiled and executed your first Java program.

Table of Contents

About This JDK Tutorial Book

►JDK (Java Development Kit)

What Is JDK

Download and Install JDK 20 on macOS

Download and Install JDK 17 on Windows

►Writing My First Java Program

Adding JDK "bin" Directory to Path Setting

JDK Documentation Installation

Check JDK Version on CentOS

Install JDK with "rpm" Command

Install JDK with "yum" Command

Java Date-Time API

Date, Time and Calendar Classes

Date and Time Object and String Conversion

Number Object and Numeric String Conversion

Locales, Localization Methods and Resource Bundles

Calling and Importing Classes Defined in Unnamed Packages

HashSet, Vector, HashMap and Collection Classes

Character Set Encoding Classes and Methods

Character Set Encoding Maps

Encoding Conversion Programs for Encoded Text Files

Java Logging

Socket Network Communication

Datagram Network Communication

DOM (Document Object Model) - API for XML Files

SAX (Simple API for XML)

DTD (Document Type Definition) - XML Validation

XSD (XML Schema Definition) - XML Validation

XSL (Extensible Stylesheet Language)

Message Digest Algorithm Implementations in JDK

Private key and Public Key Pair Generation

PKCS#8/X.509 Private/Public Encoding Standards

Digital Signature Algorithm and Sample Program

"keytool" Commands and "keystore" Files

KeyStore and Certificate Classes

Secret Key Generation and Management

Cipher - Encryption and Decryption

The SSL (Secure Socket Layer) Protocol

SSL Socket Communication Testing Programs

SSL Client Authentication

HTTPS (Hypertext Transfer Protocol Secure)

Outdated Tutorials

References

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