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{{#seo:|description=Learn how to use Phidget USB devices with Java.}}
[[Category:Language]]
[[Category:Language]]
{{OSLang|[[File:icon-Java.png|64x64px|link=|alt=Java]]|Java is a modern, object-oriented programming language maintained by Oracle.}}
__TOC__


==Introduction==
==Get Started==
With the Phidget22 library, it's easy to create Java applications that work with Phidget devices.


{{LanguageSupport|Java|the complete Phidget API, including events|all Phidget devices.|the {{Code|javac}} command line compiler as well as in integrated development environments(IDEs) such as [[#NetBeans | NetBeans]] and [[#Eclipse | Eclipse]]|}}
==Java Libraries==


==Quick Downloads==
We recommend installing the [https://www.phidgets.com/docs/Operating_System_Support Phidget drivers] for your operating system. Installing the drivers will put required .dll files in the proper place where Java will look for them. If you want to run your application on a computer without installing our drivers, see the [[#Deploying Applications|Deploying Applications]] section.


{{QuickDownloads|Java|
====macOS Considerations====
{{APIQuickDownloads|http://www.phidgets.com/documentation/JavaDoc.zip}}|
Legacy Phidgets running a HID USB stack require a driver extension (macOS 10.15 and newer) or a kernel extension (macOS 10.14 and earlier). During development, we recommend downloading the appropriate [https://www.phidgets.com/docs/OS_-_macOS#Quick_Downloads package] which will install the extension. When deploying applications, review the README in the [https://cdn.phidgets.com/downloads/phidget22/libraries/macos/Phidget22_macosdevel.zip macOS Development Files] for information about bundling the extension with your application.
{{ExampleQuickDownloads|http://www.phidgets.com/downloads/examples/JavaJNI.zip|}}|
{{ExtraLibraryQuickDownloads|http://www.phidgets.com/downloads/libraries/phidget21jar.zip|Java|(phidget21.jar)}}
{{WindowsQuickDownloads}}
{{MacQuickDownloads}}
{{LinuxQuickDownloads}}
}}


==Getting started with Java==
=====Determining USB Stack=====
To determine which USB stack your device is running, navigate to the product page and then to the specification tab, and look for the ''USB Stack'' specification. If you are using a VINT device, navigate to the product page for the VINT Hub you are using.


If you are new to writing code for Phidgets, we recommend starting by running, then modifying existing examples. This will allow you to:
[[Image:Javascript_networkserver_webusb_spec.png|center|600px|link=https://cdn.phidgets.com/docs/images/8/80/Javascript_networkserver_webusb_spec.png]]
{{ExampleCodeReasons}}


Instructions are divided up by operating system. Choose:
====Linux Considerations====
*[[#Windows(2000/XP/Vista/7)|Windows 2000 / XP / Vista / 7]]
Linux restricts access to USB devices to the root user. To run your Python application as a regular user, you'll need to [{{SERVER}}/docs/OS_-_Linux#Setting_Udev_Rules set up udev rules] on your system.
*[[#OS X |OS X]]
*[[#Linux | Linux]] (including PhidgetSBC)


==Windows (2000/XP/Vista/7)==
==Development Environment Configuration==


===Description of Library Files===
Before choosing a development environment, make sure you have the [http://www.oracle.com/technetwork/java/index.html Java Development Kit] installed.  
Java programs on Windows depend on two files, which the installers in the [[#Libraries and Drivers | Quick Downloads]] section put onto your system:
* <b>{{Code|phidget21.dll}}</b> contains the actual Phidget library, which is used at run-time.  By default, it is placed in {{Code|C:\Windows\System32}}.
* <b>{{Code|phidget21.jar}}</b> is the Phidget Java library for JDK <i><b>1.4.2</b></i> or higher. Your compiler has to know where this file is. By default, it is placed into {{Code|C:\Program Files\Phidgets}}. So, you can either point your compiler to that location, or copy and link to it in a directory for your project workspace. For more information, please see the section for your specific compiler/environment.  


If you do not want to use our installer, you can download the [http://www.phidgets.com/downloads/libraries/phidget21-x86.zip {{Code|phidget21.dll}}] as well as the [http://www.phidgets.com/downloads/libraries/phidget21jar_2.1.8.20120131.zip {{Code|phidget21.jar}}] and manually install them where you want; refer to our [[OS_-_Windows#Manual_File_Installation|Manual Installation Instructions]].
===Visual Studio Code===
 
{| style="margin:auto;" class="table-no-border mw-collapsible mw-collapsed"
Running the examples and writing your own code can be fairly compiler-specific, so we include instructions for each compiler below.
|+ '''Instructions'''
 
| To start developing with Java in VSCode, open it up and install the '''Extension Pack for Java'''.||[[Image:Language_java_vscode_extension2.png|center|350px|link=https://cdn.phidgets.com/docs/images/b/b4/Language_java_vscode_extension2.png]]
You can program Phidgets with Java in command line with the {{Code|javac}} compiler as well as in IDEs such as NetBeans and Eclipse.  
|-
 
| Next, press '''Ctrl+Shift+P''' to open the command palette, type "java" and select '''Java: Create Java Project'''.  || [[Image:Language_java_vscode_createproj.png|center|360px|link=https://cdn.phidgets.com/docs/images/7/78/Language_java_vscode_createproj.png]]
===Javac (Command Line)===
|-
 
| Select "No Build Tools" and select a directory for the new project. You'll be asked for a project name, and  VSCode will create the directory structure. || [[Image:Language_java_vscode_emptyproj.png|center|350px|link=https://cdn.phidgets.com/docs/images/c/c1/Language_java_vscode_emptyproj.png]]
====Use Our Examples====
|-
 
| colspan="2"|You'll need to get a copy of '''phidget22.jar''' to put inside the "lib" folder. [https://www.phidgets.com/downloads/phidget22/libraries/any/Phidget22Java.zip You can download phidget22.jar here].  
Download the [http://www.phidgets.com/downloads/examples/JavaJNI.zip example] and unpack them into a folder. Here, you can find an example program called HelloWorld which will work with any Phidget.  You can also find example programs for all the devices. {{FindYourDevice}} Please only use the simple examples. The full examples are intended for the [[#NetBeans | NetBeans IDE]].
|-
| colspan="2"| You can now begin writing code in the newly created "App.java" file, or you can download a [[#Example_Code|sample program]] for your device and place it in the "src" folder.
|-
| Compile and run by pressing '''F5''' or by clicking the play button in the top right. || [[Image:Language_java_vscode_run.png|center|350px|link=https://cdn.phidgets.com/docs/images/e/ea/Language_java_vscode_run.png]]
|-
| Once you're ready to compile your project into a .jar executable, click on the '''Java Projects''' section in the explorer. || [[Image:Language_java_vscode_jar.png|center|350px|link=https://cdn.phidgets.com/docs/images/6/65/Language_java_vscode_jar.png]]
|-
| Click on the export icon, and then select your main class and click OK. || [[Image:Language_java_vscode_jar2.png|center|350px|link=https://cdn.phidgets.com/docs/images/7/74/Language_java_vscode_jar2.png]]
|-
| colspan="2"| Now you can run your new .jar file with the following command:
<syntaxhighlight>
java -jar Example.jar
</syntaxhighlight>
|}


Ensure that the {{Code|phidget21.jar}} is in the same directory as the source code.
===Javac===
 
{| style="margin:auto;" class="table-no-border mw-collapsible mw-collapsed"
To compile in Windows command prompt:
|+ '''Instructions'''
<div class="source">
|The easiest way to allow Java to access the Phidgets Java library is to place a copy of '''phidget22.jar''' in the same folder as your .java program.  ||[[Image:Language_java_javac_folder.png|center|350px|link=https://cdn.phidgets.com/docs/images/8/89/Language_java_javac_folder.png]]
<syntaxhighlight lang=bash>
|-
javac -classpath .;phidget21.jar example.java
|[https://www.phidgets.com/downloads/phidget22/libraries/any/Phidget22Java.zip You can download phidget22.jar here].||
|-
|colspan="2"|To run your program, enter the following command in the command prompt or terminal:
<syntaxhighlight>
javac -classpath .;phidget22.jar example.java
</syntaxhighlight>
</syntaxhighlight>
</div>
Then, enter the following command to run the program:
 
<syntaxhighlight>
This will create Java bytecode in the form of {{Code|.class}} files. Type the following to run the program:
java -classpath .;phidget22.jar example  
<div class="source">
<syntaxhighlight lang=bash>
java -classpath .;phidget21.jar example
</syntaxhighlight>
</syntaxhighlight>
</div>
||
 
|-
 
| colspan="2"| Once you're ready to compile your project into a .jar executable, create a '''manifest.mf''' file with the following contents:
If you wish, you can compile the project as a {{Code|.jar}} so there are fewer files to maintain. The [http://www.oracle.com/java Java SDK] provides the {{Code|jar}} utility which packages all the {{Code|.class}} files into a single {{Code|.jar}} file.
<syntaxhighlight>
To begin, you will have to provide a Manifest file to indicate the program entry point. With your favourite text editor, create a new file with the following content:
<div class="source">
<syntaxhighlight lang=text>
Manifest-Version: 1.0
Manifest-Version: 1.0
Class-Path: phidget21.jar
Main-Class: example
Main-Class: example
Class-Path: phidget22.jar
 
</syntaxhighlight>
</syntaxhighlight>
<br/>
Make sure there's an empty newline at the bottom of the three lines and a space after each colon.
</div> 
|-
Ensure that the file ends in a single new line or a carriage return character.  
| colspan="2"| Next, create the .jar file with this command:
Save the file as {{Code|example.mf}} and place it in the same directory as the other {{Code|.class}} files.
<syntaxhighlight>
Next, create the .{{Code|jar}} with:
jar cfm example.jar manifest.mf *.class
<div class="source">
<syntaxhighlight lang=bash>
jar -cfm example.jar example.mf *.class
</syntaxhighlight>
</syntaxhighlight>
</div>
Once the .jar is created, you can execute it with
Afterwards, you can run the {{Code|.jar}} with:
<syntaxhighlight>
<div class="source">
<syntaxhighlight lang=bash>
java -jar example.jar
java -jar example.jar
</syntaxhighlight>
</syntaxhighlight>
</div>
Once you have the Java examples running, we have a [[#Follow the Examples|teaching]] section below to help you follow them.
=====Write Your Own Code=====
When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget Java library. Please see the [[#Use Our Examples| previous]] section for instructions.
In your code, you will need to include the Phidget Java library:
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
The project now has access to the Phidget function calls and you are ready to begin coding.
The same [[#Follow the Examples|teaching]] section which describes the examples also has further resources for programming your Phidget.
===NetBeans===
=====Use Our Examples=====
You first download the [http://www.phidgets.com/downloads/examples/JavaJNI.zip examples], unpack them into a folder, and then find the source code for your device. {{FindYourDevice}} The full examples were written in NetBeans, so the rest of this section will use these examples. To use the simple examples, you will have to import the source code into a new NetBeans project.
[[File:Java NetBeans Open Project.PNG|link=|alt=Open Project]]
The only thing left to do is to run the examples! Click on Run &rarr; Run Project. The project, by default tries to find the {{Code|phidget21.jar}} in {{Code|..\..\lib}}.
[[File:Java NetBeans Run.PNG|link=|alt=Run]]
Once you have the Java examples running, we have a [[#Follow the Examples|teaching]] section below to help you follow them.


=====Write Your Own Code=====
|}


When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget Java library. To begin:  
===Netbeans===
 
{| style="margin:auto;" class="table-no-border mw-collapsible mw-collapsed"
1. Create a new Java application project with a descriptive name such as PhidgetTest.  
|+ '''Instructions'''
 
|The easiest way to allow Java to access the Phidgets Java library is to place a copy of '''phidget22.jar''' in the same folder as your .java program.  ||[[Image:Language_java_javac_folder.png|center|350px|link=https://cdn.phidgets.com/docs/images/8/89/Language_java_javac_folder.png]]
[[File:Java NetBeans New Project.PNG|link=|alt=New Project]]
|-
 
|[https://www.phidgets.com/downloads/phidget22/libraries/any/Phidget22Java.zip You can download phidget22.jar here].||
2. Add a reference to the Phidget Java library. In the projects pane, right click {{Code|Libraries}} and add the {{Code|jar}}.
|-
 
| To start, open NetBeans and create a new project. Select Java Application and follow the steps as directed by Netbeans.|| [[Image:Windows_netbeans1.jpg|center|350px|link=https://cdn.phidgets.com/docs/images/c/c9/Windows_netbeans1.jpg]]
[[File:Java NetBeans Add Jar.PNG|link=|alt=Add Jar]]
|-
 
| Next, add a reference to phidget22.jar by right-clicking on the libraries folder. || [[Image:Windows_netbeans2.jpg|center|350px|link=https://cdn.phidgets.com/docs/images/2/2b/Windows_netbeans2.jpg]]
3. Find and select {{Code|phidget21.jar}}.
|-
 
| Navigate to the folder where you downloaded phidget22.jar, and select it. || [[Image:Windows_netbeans3.jpg|center|350px|link=https://cdn.phidgets.com/docs/images/7/76/Windows_netbeans3.jpg]]
[[File:Java NetBeans Add Jar 2.PNG|link=|alt=Add Jar]]
|-
 
| The project now has access to Phidgets. By default, Netbeans should create an executable .jar file in the '''dist''' folder of the project directory when it's built. If it didn't, go to '''Build -> Packaging''' in the project properties and make sure "Build JAR after compiling" is checked.|| [[Image:Windows_netbeans4.png|center|350px|link=https://cdn.phidgets.com/docs/images/7/78/Windows_netbeans4.png]]
4. Then, in your code, you will need to include the Phidget Java library:
|-
 
| colspan="2"| You can now run the .jar file from the command prompt with:
<div class="source">
<syntaxhighlight>
<syntaxhighlight lang=java>
java -jar phidgetTest.jar
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</syntaxhighlight>
</div>
|}
 
 
The project now has access to the Phidget function calls and you are ready to begin coding.
 
The same [[#Follow the Examples|teaching]] section which describes the examples also has further resources for programming your Phidget.


===Eclipse===
===Eclipse===
 
{| style="margin:auto;" class="table-no-border mw-collapsible mw-collapsed"
=====Use Our Examples=====
|+ '''Instructions'''
 
| To start, open Eclipse and create a new Java project. Name the project and uncheck the '''create module-info.java file''' box.|| [[Image:java_eclipse_newproj.png|center|350px|link=https://cdn.phidgets.com/docs/images/9/97/Java_eclipse_newproj.png]]
1. Download the [http://www.phidgets.com/downloads/examples/JavaJNI.zip examples] and unpack them into a folder. Here, you can find an example program called HelloWorld which will work with any Phidget.  You will also find example programs for all the devices. {{FindYourDevice}}
|-
 
| On the Libraries tab, click Add External JARs and add [https://www.phidgets.com/downloads/phidget22/libraries/any/Phidget22Java.zip phidget22.jar]. to your project as an external jar. Be sure it's being added to the '''Classpath''' and not the module path. || [[Image:java_eclipse_library.png|center|350px|link=https://cdn.phidgets.com/docs/images/1/1b/Java_eclipse_library.png]]
Please use the simple examples. The full examples were written in NetBeans, and are not compatible with Eclipse. The rest of this guide will assume that the simple examples are used. The example source code will be copied into your Eclipse project later on. Keep note of the file name of the example as a Java class will be created with the same name.
|-
 
| Create a new Class in your project. || [[Image:java_eclipse_newclass.png|center|350px|link=https://cdn.phidgets.com/docs/images/0/02/Java_eclipse_newclass.png]]
2. Generate a new Java project with a descriptive name such as PhidgetTest. Click next.
|-
 
| Name the class, and be sure to check the '''public static void main''' box. Eclipse may require that you add a package name. || [[Image:java_eclipse_newclass2.png|center|350px|link=https://cdn.phidgets.com/docs/images/c/ca/Java_eclipse_newclass2.png]]
[[File:Java Eclipse New Project.PNG|link=|alt=New Project]]
|-
 
| Your project now has access to Phidgets! ||
3. On the next screen, go to the libraries panel and add an external {{Code|jar}}.
|-
 
| Once you're ready to compile your project into a .jar executable, right click on the project in the package explorer and choose '''Export'''. Select '''Runnable JAR file'''. || [[Image:java_eclipse_export.png|center|350px|link=https://cdn.phidgets.com/docs/images/8/8c/Java_eclipse_export.png]]
[[File:Java Eclipse Add Jar 1.PNG|link=|alt=Add Jar]]
|-
 
| Choose the main class and a destination for the .jar file and click finish. || [[Image:java_eclipse_export2.png|center|350px|link=https://cdn.phidgets.com/docs/images/8/8d/Java_eclipse_export2.png]]
4. Find and select {{Code|phidget21.jar}}.
|-
 
| colspan="2"| You can now run the .jar file from the command prompt with:
[[File:Java Eclipse Add Jar 2.PNG|link=|alt=Add Jar]]
<syntaxhighlight>
 
java -jar phidgetTest.jar
5. Add a new Java class to the project.
 
[[File:Java Eclipse New Class.PNG|link=|alt=New Class]]
 
6. Name this class with the same name as the simple example's name.
 
[[File:Java Eclipse New Class 2.PNG|link=|alt=New Class]]
 
7. Copy and paste the example source code over to the class you created.
 
[[File:Java Eclipse Source.PNG|link=|alt=Source Code]]
 
8. The only thing left to do is to run the examples!
 
[[File:Java Eclipse Run.PNG|link=|alt=Run]]
 
 
Once you have the Java examples running, we have a [[#Follow the Examples|teaching]] section below to help you follow them.
 
=====Write Your Own Code=====
 
When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget Java library. Please see the [[#Use Our Examples 3| Use Our Examples]] section for instructions.
 
In your code, you will need to include the Phidget Java library:
 
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
 
The project now has access to the Phidget function calls and you are ready to begin coding.
 
The same [[#Follow the Examples|teaching]] section which describes the examples also has further resources for programming your Phidget.
 
==OS X==
 
The first step in using Java on Mac is to install the Phidget libraries. Compile and install them as explained on the [[OS - OS X|main Mac OS page]].  That page also describes the different Phidget files, their installed locations, and their roles.
 
===Use Our Examples===
 
The commands to compile in a OS X and Windows terminal are slightly different. Rather than prefixing {{Code|phidget21.jar}} with a semi-colon( {{Code|;}} ), a colon( {{Code|:}} ) is used.  Make sure that the {{Code|phidget21.jar}} file is in the same directory as the code you are trying to compile. 
 
<div class="source">
<syntaxhighlight lang=bash>
javac -classpath .:phidget21.jar example.java
</syntaxhighlight>
</div>
 
Then, to run the program:
 
<div class="source">
<syntaxhighlight lang=bash>
java -classpath .:phidget21.jar example
</syntaxhighlight>
</div>
 
This method can be used on any of the simple examples.  If you are interested in using an IDE then refer to the [[Language - Java#Windows (2000/XP/Vista/7)|Windows]] section for information about setting up Phidgets projects in Eclipse or NetBeans.
 
===Write Your Own Code===
With the method just discussed, notice that you need to link the {{Code|phidget21.jar}} both at compile, and runtime.  An alternative is to make a jar file of your program which includes the Phidget Java library.  To do this first create a manifest file. A manifest is a text file used to define package related data.  Make a text file called {{Code|MyProgram.mf}}, where {{Code|MyProgram}} is replaced by the name of your main class.  Put the following lines into {{Code|MyProgram.mf}}:
 
<div class="source">
<syntaxhighlight lang=text>
Manifest-Version: 1.0
Class-Path: phidget21.jar
Main-Class: MyProgram
 
 
</syntaxhighlight>
</div>
 
'''Note:''' The manifest file should end with a carriage return. So, there should be an extra line at the bottom of the file.
 
After creating the manifest file, you can use the {{Code|jar}} function to create one self-contained file with your classes and the correct classpath.
 
<div class="source">
<syntaxhighlight lang=bash>
jar –cfm MyProgram.jar MyProgram.mf *.class
</syntaxhighlight>
</div>
 
If porting this for an external system, such as one that your customer would be running, the Phidget library would need to be compiled and distributed along with the {{Code|.jar}}.  Although we do not directly support this, if you are interested in how to construct this, we provide both a distribution example and information on cross-compiling:
* The [[Language - Android Java | Android Java]] libraries have an ARM-compiled {{Code|libphidget21.so}} file included, as an example of distributing a compiled libphidget21.so with the jar file
* The [[OS - Linux#Cross-Compiling with a Custom Toolchain|Linux page]] has more detail for compiling the Phidget C Libraries for an external target.
 
===NetBeans===
 
We offer in-depth tutorials on using our examples in NetBeans and Eclipse in the [[#NetBeans|Windows NetBeans]] and [[#Eclipse|Windows Eclipse]] sections.
 
As our full examples are written with NetBeans, but NetBeans is not part of the standard OS X application suite., we offer installation instructions here before referring to the Windows sections.
 
====Installation====
To install NetBeans on a Mac, all  you have to do is download the installer from [www.netbeans.org their website] and run it.
 
====Use Our Examples====
 
Once you have NetBeans installed, running our examples will be very similar to the process described in the [[#NetBeans|Windows NetBeans]] section.
 
====Write Your Own Code====
 
When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget Java library. Please see the [[#NetBeans| Windows NetBeans]] section for instructions if you are unfamiliar with NetBeans.
 
In your code, you will need to include the Phidget Java library:
 
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
 
The project now has access to the Phidget function calls and you are ready to begin coding.
 
The [[#Follow the Examples|teaching]] section - which describes the examples - also has further resources for programming your Phidget.
 
==Linux==
 
Java has excellent support on Linux - there is an established implementation of the Java compiler and interpreter, and several Integrated Development Environments (IDEs) including NetBeans and Eclipse.  
 
The first step in using Java on Linux is to install the base Phidget libraries. Compile and install them as explained on the main [[OS - Linux | Linux page]].  That Linux page also describes the different basic Phidget library files, their installed locations, and their roles.
 
You will also need the [http://www.phidgets.com/downloads/libraries/phidget21jar.zip Phidget Java Libraries (phidget21.jar)].
 
Once downloaded, the {{Code|phidget21.jar}} library file does not get 'installed' (i.e. do not run {{Code| java -jar phidget21.jar}}).  Rather, the library file gets put into the path of whatever program you write, and you will link it via both the java compiler and the java interpreter.  We walk you through this below.
 
We have two different types of Phidget examples in Java:
*Simple examples, to be run on the command line, and
*Full examples, to be run in NetBeans
 
Both are contained within the [http://www.phidgets.com/downloads/examples/JavaJNI.zip Phidget Java example download package].
 
===Description of Library Files===
 
The Phidget Java libraries depend on the C libraries being installed as explained on the main [[OS - Linux | Linux page]].  If you browse around within the phidget21.jar archive, you will find Java class files (too many to reasonably list here) that have names related to the devices they provide an API for.
 
These Java class files use the functions available in the ''dynamic'' Phidget21 C-language library on Linux.  Dynamic libraries end with {{Code|.so}}, and so the C library that the Phidget Java class files use is {{Code|/usr/lib/libphidget21.so}}.
 
===Javac (Command Line)===
 
====Use Our Examples====
 
Linux gets somewhat complicated in that two Java compilers exist: {{Code|openjdk}} and {{Code|gcj}}.  Furthermore, a given IDE can ''usually'' use either compiler. That being said, we only offer support here for openJDK and IDEs running openJDK.
 
To find out which type of compiler your computer has, use the {{Code|-version}} option on the command line.  You can use the same option for your runtime environment (interpreter):
 
<div class="source">
<syntaxhighlight lang=text>
$> java -version
java version "1.6.0_23"
OpenJDK Runtime Environment (IcedTea6 1.11pre) (6b23~pre11-0ubuntu1.11.10.1)
OpenJDK 64-Bit Server VM (build 20.0-b11, mixed mode)
 
$> javac -version
javac 1.6.0_23
</syntaxhighlight>
</syntaxhighlight>
</div>
|}
 
The good news is that you can have both {{Code|openjdk}} and {{Code|gcj}} on your machine, co-habitating happily.  There can be only one linked java and javac in {{Code|/usr/bin/}} however, and so this will correspond to whichever java compiler and interpreter you installed last.
 
If you do not have {{Code|openjdk}} installed already (this is the default Java installation for most Linux machines, so you will probably know), and you choose to install it for Phidget purposes, it is important is that the {{Code|java}} version be greater than the {{Code|javac}} version.  Otherwise, your runtime environment will consider the stuff your compiler produces to be newfangled nonsense.  So when installing Java from a repository, you should install both the jdk and the jre.  These are, unfortunately, usually separate packages in a repository (e.g. {{Code|openjdk-7-jre}} and {{Code|openjdk-7-jdk}}).
 
The simple examples in Java are meant to be compiled and run on the command line.  The example package includes a {{Code|Makefile}} so you can either make all of the examples at once, with:
 
<div class="source">
<syntaxhighlight lang=bash>
make all
</syntaxhighlight>
</div>
 
...Or you can make them individually.  You can either use:
* The HelloWorld example, which will work with any Phidget, or
* The example with the name that corresponds to the family (software object) of your Phidget hardware. 
{{FindYourDevice}}  Once you've identified the right example - say, {{Code|HelloWorld.java}} - compile it on the command line with:
 
<div class="source">
<syntaxhighlight lang=bash>
javac -classpath .:phidget21.jar HelloWorld.java
</syntaxhighlight>
</div>
 
To run the example on a Linux machine [[OS - Linux#Setting udev Rules| without your udev USB rules set]], you will need to run the Java example as root:
 
<div class="source">
<syntaxhighlight lang=bash>
sudo java -classpath .:phidget21.jar HelloWorld
</syntaxhighlight>
</div>
 
====Write Your Own Code====
 
You'll note that the Phidget Java library file {{Code|phidget21.jar}} needs to be explicitly linked at both points in the compile and run process.  Alternatively, you can make a jar file which includes the Phidget Java library.  This process takes two steps, the first of which is creating a text file called {{Code|MyProgram.mf}}, where {{Code|MyProgram}} is replaced by the name of your main class in both the filename and the text below:
 
<div class="source">
<syntaxhighlight lang=text>
Manifest-Version: 1.0
Class-Path: phidget21.jar
Main-Class: MyProgram
 
</syntaxhighlight>
</div>
 
'''Note:''' The manifest file should end with a carriage return. So, there should be an extra line at the bottom of the file.
 
After creating the manifest file, you can use the {{Code|jar}} function to create one self-contained file with your classes and the correct classpath.
 
<div class="source">
<syntaxhighlight lang=bash>
jar –cfm MyProgram.jar MyProgram.mf *.class
</syntaxhighlight>
</div>
 
If porting this for an external system, such as one that your customer would be running, the Phidget library would need to be compiled and distributed along with the {{Code|.jar}}.  Although we do not directly support this, if you are interested in how to construct this, we provide both a distribution example and information on cross-compiling:
* The [[Language - Android Java | Android Java]] libraries have an ARM-compiled {{Code|libphidget21.so}} file included, as an example of distributing a compiled libphidget21.so with the jar file
* The [[OS - Linux#Cross-Compiling with a Custom Toolchain|Linux page]] has more detail for compiling the Phidget C Libraries for an external target.
 
===NetBeans===
 
We offer in-depth tutorials on using our examples in NetBeans and Eclipse in the [[#NetBeans|Windows NetBeans]] and [[#Eclipse|Windows Eclipse]] sections.
 
As our full examples are written with NetBeans, but NetBeans is not part of the standard Linux package repository, we offer installation instructions here before referring to the Windows sections.
 
====Installation====
 
Although Eclipse is standard in the Debian/Ubuntu package repository, NetBeans is no longer standard.  What is more, Netbeans does not install by default into a folder within your path.  As our Phidget full Java examples are written using NetBeans, we provide basic installation instructions here so you can actually run them.
 
To install NetBeans:
 
1. Download the install script from website: [http://netbeans.org/downloads/ http://netbeans.org/downloads/]<br>
2. Change the permissions of the downloaded file to be executable.  Usually, this is something like:
:{{Code|chmod +x netbeans-7.1-ml-javase-linux.sh}}<br>
3. Run the downloaded file as a script. (This will result in a GUI interaction that walks you through installation.)<br>
4. To find the location where the NetBeans installation occurred, run:<br>
:{{Code|updatedb}}
:{{Code|locate netbeans | grep bin}}<br>
5. Usually, the location of the binary is {{Code|/usr/local/netbeans-7.1/bin/netbeans}}, where 7.1 is the installed version.
 
====Use Our Examples====
 
Once you have NetBeans installed, running our examples will be very similar to the process described in the [[#NetBeans|Windows NetBeans]] section.
 
====Write Your Own Code====
 
When you are building a project from scratch, or adding Phidget function calls to an existing project, you'll need to configure your development environment to properly link the Phidget Java library. Please see the [[#NetBeans| Windows NetBeans]] section for instructions if you are unfamiliar with NetBeans.
 
In your code, you will need to include the Phidget Java library:
 
<div class="source">
<syntaxhighlight lang=java>
import com.phidgets.*;
import com.phidgets.event.*;
</syntaxhighlight>
</div>
 
The project now has access to the Phidget function calls and you are ready to begin coding.
 
The [[#Follow the Examples|teaching]] section - which describes the examples - also has further resources for programming your Phidget.


==Follow the Examples==
=== PhidgetSBC Web Interface ===
{| style="margin:auto;" class="table-no-border mw-collapsible mw-collapsed"
|+'''Instructions'''
|<center>{{#ev:youtube|gZmWvWXICIA|rel=0}}</center>
|}


By following the instructions for your operating system and compiler above, you probably now have a working example and want to understand it better so you can change it to do what you want. This teaching section has resources for you to learn from the examples and write your own.
==Example Code==
Navigate to our [https://www.phidgets.com/?view=code_samples&lang=Java Code Sample Generator] to view and download code samples that are tailored to your specific device.


Your main reference for writing Java code will be our Java API information, with syntax for all of our functions:
[[Image:Language_java_codesample.png|center|600px|link=https://cdn.phidgets.com/docs/images/a/af/Language_java_codesample.png]]


{{UsingAPhidgetInCodeGeneral|both of which are available in Java|[http://www.phidgets.com/documentation/JavaDoc.zip Java API]}}
===Phidget Programming Basics===
{{PhidgetProgrammingBasicsLink}}


===Example Flow===
==API==
[{{SERVER}}/?view=api&lang=Python Phidget22 API]


{{ExamplePseudocode|In Java, it is easiest if you name these '''event''' functions the same as in our examples.  You can change the main function pointer variable name, but none of the other names.  Our examples show how to immediately hook these functions into the events that will call them <br> <br>
== Deploying Applications ==
In the example code, the event functions common to all Phidgets are called things like '''AttachHandler()''' and '''DetachHandler()''', etc.<br>
But some event functions will be specific to each device, like when a tag is read on an RFID board, or when a sensor value changes on an Interface Kit.  Some 'get data' functions are also specific to each device.
|Creating a Phidget software object in Java - when you are not using the Manager - is specific to the Phidget.  For a Phidget Spatial, for example, this would involve creating a {{Code|SpatialPhidget}} object.  The device-specific examples show how to do this and other API functions.<br><br>
The software object provides device specific methods which are available from the API for your specific Phidget.|
[http://www.phidgets.com/documentation/JavaDoc.zip Java API]}}


===Code Snippets===
If you're planning to deploy your application, it should be noted that you don't strictly need the Phidget Drivers installed.


When programming in Java, you're in luck. All of our code snippet examples on our [[General Phidget Programming]] page are in both C++ and Java. Therefore, we do not include any here, because that page is much more in-depth, and you won't have to have two pages open at once. So head over there, and start writing code!
At a minimum, these three files are required:
* phidget22.jar
* phidget22.dll
* phidget22java.dll


==Common Problems and Solutions/Workarounds==
All three files can be found in the [https://cdn.phidgets.com/downloads/phidget22/libraries/windows/Phidget22-windevel.zip Development Files]. The .jar file is in lib/java, and the .dll files are in lib/c/x64.


None yet.
Java will look for these files in several locations, including the classpath and the working folder of the project.

Latest revision as of 20:05, 1 April 2026


Get Started

With the Phidget22 library, it's easy to create Java applications that work with Phidget devices.

Java Libraries

We recommend installing the Phidget drivers for your operating system. Installing the drivers will put required .dll files in the proper place where Java will look for them. If you want to run your application on a computer without installing our drivers, see the Deploying Applications section.

macOS Considerations

Legacy Phidgets running a HID USB stack require a driver extension (macOS 10.15 and newer) or a kernel extension (macOS 10.14 and earlier). During development, we recommend downloading the appropriate package which will install the extension. When deploying applications, review the README in the macOS Development Files for information about bundling the extension with your application.

Determining USB Stack

To determine which USB stack your device is running, navigate to the product page and then to the specification tab, and look for the USB Stack specification. If you are using a VINT device, navigate to the product page for the VINT Hub you are using.

Javascript networkserver webusb spec.png

Linux Considerations

Linux restricts access to USB devices to the root user. To run your Python application as a regular user, you'll need to set up udev rules on your system.

Development Environment Configuration

Before choosing a development environment, make sure you have the Java Development Kit installed.

Visual Studio Code

Instructions
To start developing with Java in VSCode, open it up and install the Extension Pack for Java.
Language java vscode extension2.png
Next, press Ctrl+Shift+P to open the command palette, type "java" and select Java: Create Java Project.
Language java vscode createproj.png
Select "No Build Tools" and select a directory for the new project. You'll be asked for a project name, and VSCode will create the directory structure.
Language java vscode emptyproj.png
You'll need to get a copy of phidget22.jar to put inside the "lib" folder. You can download phidget22.jar here.
You can now begin writing code in the newly created "App.java" file, or you can download a sample program for your device and place it in the "src" folder.
Compile and run by pressing F5 or by clicking the play button in the top right.
Language java vscode run.png
Once you're ready to compile your project into a .jar executable, click on the Java Projects section in the explorer.
Language java vscode jar.png
Click on the export icon, and then select your main class and click OK.
Language java vscode jar2.png
Now you can run your new .jar file with the following command:
java -jar Example.jar

Javac

Instructions
The easiest way to allow Java to access the Phidgets Java library is to place a copy of phidget22.jar in the same folder as your .java program.
Language java javac folder.png
You can download phidget22.jar here.
To run your program, enter the following command in the command prompt or terminal:
javac -classpath .;phidget22.jar example.java

Then, enter the following command to run the program:

java -classpath .;phidget22.jar example
Once you're ready to compile your project into a .jar executable, create a manifest.mf file with the following contents:
Manifest-Version: 1.0
Main-Class: example
Class-Path: phidget22.jar
 

Make sure there's an empty newline at the bottom of the three lines and a space after each colon.

Next, create the .jar file with this command:
jar cfm example.jar manifest.mf *.class

Once the .jar is created, you can execute it with

java -jar example.jar

Netbeans

Instructions
The easiest way to allow Java to access the Phidgets Java library is to place a copy of phidget22.jar in the same folder as your .java program.
Language java javac folder.png
You can download phidget22.jar here.
To start, open NetBeans and create a new project. Select Java Application and follow the steps as directed by Netbeans.
Windows netbeans1.jpg
Next, add a reference to phidget22.jar by right-clicking on the libraries folder.
Windows netbeans2.jpg
Navigate to the folder where you downloaded phidget22.jar, and select it.
Windows netbeans3.jpg
The project now has access to Phidgets. By default, Netbeans should create an executable .jar file in the dist folder of the project directory when it's built. If it didn't, go to Build -> Packaging in the project properties and make sure "Build JAR after compiling" is checked.
Windows netbeans4.png
You can now run the .jar file from the command prompt with:
java -jar phidgetTest.jar

Eclipse

Instructions
To start, open Eclipse and create a new Java project. Name the project and uncheck the create module-info.java file box.
Java eclipse newproj.png
On the Libraries tab, click Add External JARs and add phidget22.jar. to your project as an external jar. Be sure it's being added to the Classpath and not the module path.
Java eclipse library.png
Create a new Class in your project.
Java eclipse newclass.png
Name the class, and be sure to check the public static void main box. Eclipse may require that you add a package name.
Java eclipse newclass2.png
Your project now has access to Phidgets!
Once you're ready to compile your project into a .jar executable, right click on the project in the package explorer and choose Export. Select Runnable JAR file.
Java eclipse export.png
Choose the main class and a destination for the .jar file and click finish.
Java eclipse export2.png
You can now run the .jar file from the command prompt with:
java -jar phidgetTest.jar

PhidgetSBC Web Interface

Instructions

Example Code

Navigate to our Code Sample Generator to view and download code samples that are tailored to your specific device.

Language java codesample.png

Phidget Programming Basics

To learn more about the structure of the example code, visit our Phidget Programming Basics guide.

API

Phidget22 API

Deploying Applications

If you're planning to deploy your application, it should be noted that you don't strictly need the Phidget Drivers installed.

At a minimum, these three files are required:

  • phidget22.jar
  • phidget22.dll
  • phidget22java.dll

All three files can be found in the Development Files. The .jar file is in lib/java, and the .dll files are in lib/c/x64.

Java will look for these files in several locations, including the classpath and the working folder of the project.