Mac OS X and iOS developers are intimately familiar with Apple's Xcode development environment. Xcode is a full-feature tool that helps software developers produce rich applications for Mac OS X and iOS. Developers for iOS and OS X traditionally develop their applications using the Objective-C and Cocoa (Cocoa Touch for iOS) application framework. However, some software engineers prefer to work with alternative software development tools. One popular choice is Java. Knowing this, Apple has made developing Java-based applications easy using Xcode.
Step 1
Verify that Java is installed on your system. To do this, open a terminal and type the following command: Java -version. Mac OS X comes pre-installed with the Java runtime environment and its corresponding Java developer kit (JDK), so you should see a version of Java printed out in the terminal. As of June 2011 the current version of Java for Mac OS X is Java 1.6, so if you see a lower version number printed out in your terminal, then you need to update your system's software via the built-in software update tool.
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Step 2
Open Xcode and create a new project based on the empty template under the OS X tab. Users familiar with out-of-date versions of Xcode (the current version of Xcode as of June 2011 is Xcode 4) might remember that there used to be templates dedicated to different types of Java applications, but this is no longer the case. You will be presented with a completely bare Xcode project.
Step 3
Create the Java main file for your application by selecting "New File" from the file menu and naming the file "Main" with the ".java" extension; all Java applications must have a main file.
Step 4
Right-click on the left pane of the IDE and select the "Add Group" option. This will create a folder with a name of your own choosing within the project, allowing you to organize your Xcode project in a logical manner.
Step 5
Begin writing the code for your application. Assuming there is nothing wrong with your Xcode installation or your Java installation, Xcode should automatically provide syntax highlighting for your Java code.
How to Downgrade Java
Oracle recommends every computer have the latest version of Java. Without it, you could be at risk for a security breach. That said, occasionally you may come across an application that requires an older version of Java, which means your only option is a Java rollback. The best thing to do in that situation is to try to find an alternative application, but if you have no other choice, you need to download the older Java Mac or Windows versions.
How to Downgrade Java
Before you downgrade Java, Oracle recommends first removing all older versions from your computer. After you do that, go to Oracle's Older Java Archive, where you'll see a list of download files. When you click on a file, you are directed to a page where you can get Java for Mac, Windows or Linux. Oracle recommends reporting the need for an older version to the developer of the application requiring it because it puts your device at risk.
Uninstall a Java Update
In some cases, you need to downgrade Java has to do with an update that wreaked havoc with your system. Maybe it's incompatible with something else you're using, or perhaps there's a bug that Java hasn't fixed yet. You can do a Java rollback in this instance by uninstalling the update. In Windows, go to the Control Panel and choose "Apps." Scroll down until you see the update on the list. From there, you can uninstall it. Only install the most recent version. If an older version is installed, leave it in place. If you have a Mac, go to your Finder. Choose "Go," followed by "Utilities." Click on "Terminal" and copy and paste the following commands:
sudo rm -fr /Library/Internet\ Plug-Ins/JavaAppletPlugin.plugin
sudo rm -fr /Library/PreferencePanes/JavaControlPanel.prefPane
sudo rm -fr ~/Library/Application\ Support/Oracle/Java
You can also uninstall Java using the Java uninstaller tool that available at the Java website. Once you remove Java, find the most recent version before the problematic one on Oracle's website and install it.
Remove Old Java Versions
If you're experiencing a problem with Java, it could be that you have older versions residing on your computer. Instead of a Java rollback, make sure you have only the most recent version. If you find old versions, Java for Mac owners need to either enter commands into the terminal or use the Java uninstall tool. If you have a Windows machine, though, you can go to "Apps" in the Control Panel and uninstall all but the most recent version from there.
How to Check to See if I Need Java Updates
Java software gives you the option to set the Java version parameter for handling the Java applets that run in your Web browser and update your version of Java. If you are not sure what version of Java you are running, you need to check the version of Java software installed on your computer by using the Java Control Panel. By checking the panel settings, you can verify if you need to update your Java software to ensure the support for the Java applets in your Web browser.
Step 1
Open the "Start" menu and then click "Control Panel." Click on the "Java" icon to open the Java Control Panel window.
Step 2
Click the "About" button in the "General" tab to see the version of Java software installed on your computer.
Step 3
Click the "Java" tab and then click "View" in the "Java-Applet Runtime Settings" section of the window. Note the version number in the "Version" column of the "Java Runtime Versions" box and compare the Java Runtime setting with the version of your Java software to see if you need to update your Java software.
