Welcome to the Mac OS X Java Frequently Asked Questions (FAQ) for developers. This page is intended to provide answers to frequently asked questions about the direction and current features of Java on Mac OS X, as well as common development questions and problems. Due to the high volume of email we receive, we cannot respond to every question or suggestion, but we are interested in what you have to say. If after reading the Java Developer FAQ, you still have a question, please contact us.

Please note that the “Common Development Questions” and “Known Issues” sections pertain to J2SE 1.4 or later unless otherwise noted. For 1.3.1 development issues, please see our Java Documentation section for Technical Notes and Q&As regarding J2SE 1.3.1 on Mac OS X.

Known Issues

1. UnsupportedClassVersionError with J2SE 5.0 Release 4.
2. Java crashes after installing a Mac OS X Update.
3. Control-drags and right-drags do not work on Mac OS X.
4. A default about box still appears after I implement handleAbout
5. My server process spawns a Dock icon when making AWT calls.
6. My double-clickable app’s custom dock icon is ignored.

1. My application throws UnsupportedClassVersionError when built with J2SE 5.0 Release 4.

Your application likely runs under 1.4 but is now built with 1.5 after upgrading, resulting in incompatible bytecode. See Technical Q&A QA1474 for details on avoiding this problem. Back to Top 

2. Java crashes after installing a Mac OS X Update.

Developers or users experiencing repeated crashes when attempting to launch Java applications from the desktop or Terminal can find steps to resolve the problem on the AppleCare website. The AppleCare article discusses an update for Mac OS X 10.3.9 which fixes the problem. If the problem appears on Mac OS X 10.4 and later, do not install the update but instead follow the instructions in the "Optional: Restoring the Java Shared Archive" section.
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3. Control-drags and right-drags do not work on Mac OS X.

This is an irreconcilable platform difference discussed in Technical Q&A QA1362.
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4. A default about box still appears after I implement handleAbout.

When implementing the handleAbout method in an ApplicationListener, the ApplicationEvent you receive needs to be handled properly in order to prevent the default dialog. This is discussed in Technical Q&A QA1363.
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5. My server process spawns a Dock icon when making AWT calls.

This is an avoidable behavior that is described in Technical Q&A QA1328.
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6. My double-clickable app’s custom dock icon is ignored.

This is a known issue that is related to the deprecated com.apple.mrj.application.apple.menu.about.name runtime property. The "Making User Interface Decisions" section of Java 1.4 Development for Mac OS X recommends using the system-standard CFBundleName property in your Info.plist, which not only avoids this problem, but also allows you to localize your application name using standard Mac OS X bundling techniques.
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