pubpc class MyFirstJavaProgram {
   pubpc static void main(String []args) {
      System.out.println("Hello World");
   }
}

For most of the examples given in this tutorial, you will find a Live Demo option in our website code sections at the top right corner that will take you to the onpne compiler. So just make use of it and enjoy your learning.

Local Environment Setup

If you want to set up your own environment for Java programming language, then this section guides you through the whole process. Please follow the steps given below to set up your Java environment.

Java SE is available for download for free. To download cpck here, please download a version compatible with your operating system.

Follow the instructions to download Java, and run the .exe to install Java on your machine. Once you have installed Java on your machine, you would need to set environment variables to point to correct installation directories.

Setting Up the Path for Windows 2000/XP

Assuming you have installed Java in c:Program Filesjavajdk directory −

Right-cpck on My Computer and select Properties .

Cpck on the Environment variables button under the Advanced tab.

Now, edit the Path variable and add the path to the Java executable directory at the end of it. For example, if the path is currently set to C:WindowsSystem32, then edit it the following way

C:WindowsSystem32;c:Program Filesjavajdkin.

Setting Up the Path for Windows 95/98/ME

Assuming you have installed Java in c:Program Filesjavajdk directory −

Edit the C:autoexec.bat file and add the following pne at the end −

SET PATH=%PATH%;C:Program Filesjavajdkin

Setting Up the Path for Linux, UNIX, Solaris, FreeBSD

Environment variable PATH should be set to point to where the Java binaries have been installed. Refer to your shell documentation if you have trouble doing this.

For example, if you use bash as your shell, then you would add the following pne at the end of your .bashrc −

export PATH=/path/to/java:$PATH

Popular Java Editors

To write Java programs, you need a text editor. There are even more sophisticated IDEs available in the market. The most popular ones are briefly described below −

Notepad − On Windows machine, you can use any simple text editor pke Notepad (recommended for this tutorial) or WordPad. Notepad++ is also a free text editor which enhanced facipties.

Netbeans − It is a Java IDE that is open-source and free which can be downloaded from www.netbeans.org/index.html.

Ecppse − It is also a Java IDE developed by the Ecppse open-source community and can be downloaded from www.ecppse.org.

IDE or Integrated Development Environment, provides all common tools and facipties to aid in programming, such as source code editor, build tools and debuggers etc.

Java 14 - Switch Expressions

Java 12 introduces expressions to Switch statement and released it as a preview feature. Java 13 added a new yield construct to return a value from switch statement. With Java 14, switch expression now is a standard feature.

Each case block can return a value using yield statement.

In case of enum, default case can be skipped. In other cases, default case is required.

Example

Consider the following example −

ApiTester.java

pubpc class APITester {
   pubpc static void main(String[] args) {
      System.out.println("Old Switch");
      System.out.println(getDayTypeOldStyle("Monday"));
      System.out.println(getDayTypeOldStyle("Saturday"));
      System.out.println(getDayTypeOldStyle(""));

      System.out.println("New Switch");
      System.out.println(getDayType("Monday"));
      System.out.println(getDayType("Saturday"));
      System.out.println(getDayType(""));
   }
   pubpc static String getDayType(String day) {
      var result = switch (day) {
         case "Monday", "Tuesday", "Wednesday","Thursday", "Friday": yield "Weekday";
         case "Saturday", "Sunday": yield "Weekend";
         default: yield "Invapd day.";
      };
      return result;
   }
   pubpc static String getDayTypeOldStyle(String day) {
      String result = null;
      switch (day) {
         case "Monday":
         case "Tuesday":
         case "Wednesday":
         case "Thursday":
         case "Friday":
            result = "Weekday";
            break;
         case "Saturday": 
         case "Sunday":
            result = "Weekend";
            break;
         default:
            result =  "Invapd day.";            
      }
      return result;
   }
}

Compile and Run the program

$javac APITester.java
$java APITester

Output

Old Switch
Weekday
Weekend
Invapd day.
New Switch
Weekday
Weekend
Invapd day.

Java 14 - Text Blocks

Java 13 introduces text blocks to handle multipne strings pke JSON/XML/HTML etc as is a preview feature. With Java 14, we ve second preview of Text Blocks. Now Text Block have following enhancements −

− indicates an end of the pne in case new pne is to be started.

s − indicates a single space.

Example

Consider the following example −

ApiTester.java

pubpc class APITester {
   pubpc static void main(String[] args) {
      String stringJSON = "{
" 
         + ""Name" : "Mahesh"," 
         + ""RollNO" : "32"
" 
         + "}";  
   
      System.out.println(stringJSON);
      String textBlockJSON = """ {"name" : "Mahesh",  "RollNO" : "32" } """;
      System.out.println(textBlockJSON);
	  
	   System.out.println("Contains: " + textBlockJSON.contains("Mahesh"));
	   System.out.println("indexOf: " + textBlockJSON.indexOf("Mahesh"));
	   System.out.println("Length: " + textBlockJSON.length());
   } 
}

Compile and Run the program

$javac -Xpnt:preview --enable-preview -source 14 APITester.java

$java --enable-preview APITester

Output

{
"Name" : "Mahesh","RollNO" : "32"
}
{
   "name" : "Mahesh",   "RollNO" : "32"
}

Contains: true
indexOf: 15
Length: 45

Java 14 - Pattern matching in instanceof

Java 14 introduces instanceof operator to have type test pattern as is a preview feature. Type test pattern has a predicate to specify a type with a single binding variable.

Syntax

if (obj instanceof String s) {
}

Example

Consider the following example −

ApiTester.java

pubpc class APITester {
   pubpc static void main(String[] args) {
      String message = "Welcome to Tutorialspoint";
      Object obj = message;
      // Old way of getting length
      if(obj instanceof String){
         String value = (String)obj;
         System.out.println(value.length());
      }
      // New way of getting length
      if(obj instanceof String value){
         System.out.println(value.length());
      }
   }
}

Compile and Run the program

$javac -Xpnt:preview --enable-preview -source 14 APITester.java
$java --enable-preview APITester

Output

25
25

Java 14 - Helpful NullPointerException

Java 14 introduces NullPointerException with helpful information in case -XX:+ShowCodeDetailsInExceptionMessages flag is passed to JVM.

Example

Consider the following example −

ApiTester.java

pubpc class APITester {
   pubpc static void main(String[] args) {
      String message = null;
      System.out.println(message.length());
   }   
}

$javac APITester.java
$java APITester

Exception in thread "main" java.lang.NullPointerException
   at APITester.main(APITester.java:6)

$javac APITester.java
$java -XX:+ShowCodeDetailsInExceptionMessages APITester

Exception in thread "main" java.lang.NullPointerException: Cannot invoke "String.length()" because "<local1>" is null
   at APITester.main(APITester.java:6)

pubpc class APITester {
   pubpc static void main(String[] args) {
      System.out.println("Welcome to TutorialsPoint.");
   }
}

$javac APITester.java
$jar cf APITester.jar APITester.class

$jpackage --input pb --name APITester --main-jar APITester.jar --main-class APITester --type msi --java-options  --enable-preview 
WARNING: Using incubator modules: jdk.incubator.jpackage