I had this exact problem. Below is how I solved it.
It looks like more work than it really is. If I accidentally deleted a step trying to format all this text, let me know.
First, on your Mac, you should find the "default Java from Apple" residing at: /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin/java
From the Eclipse menu: Eclipse> Preferences> Java> Installed JRE's>
- CLICK "Add.."
- SELECT "Mac OS X VM"
- CLICK "Next.."
In the 'JRE Definition dialog' that comes up,
- SELECT "Directory.." next to JRE Home,
- DRILL DOWN and SELECT /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin/.
Finish filling out what is needed, and then,
- SELECT java 1.6 in Eclipse> Preferences> Java> Installed JRE's>
- SELECT Eclipse> Preferences> Java> Installed JRE's> Execution Environment>.
- CLICK on "JavaSE-1.6",
and make sure that your Java 1.6 Runtime you just set up is checked.
RIGHT CLICK on your project folder in the workbench to open your projects properties, and double-check that Java 1.6 is good to go under the "Java Compiler" menu and sub-menu's.
While still in your project's properties dialog:
- CLICK "Run/Debug Settings"
- SELECT your project's name,
- CLICK "Edit.."
In the resulting dialog, 'Edit launch configuration properties':
- CLICK the "JRE" tab and ensure it's Java 1.6
- SELECT the "Classpath" tab and double check that it also is including Java 1.6
In the 'Project Explorer' tab, within your project, find the "JRE System Library" amongst your project's folders. Make sure it say's Java 1.6
- RIGHT CLICK it
- SELECT "Properties"
- CHECK MARK "Execution Environment", and in the drop down menu, SELECT JavaSE-1.6
I'll confess, it is late and I'm hurrying, so changing every reference from 1.7 to 1.6 I have it working as I write this. In fact, I JUST got it working, so am sharing this before I get at it!
The BELOW step I also did. In my case, I was running Indigo 3.7 on Mac Mavericks. If the above still isn't working, this is the other thing I added in my situation.
- RIGHT CLICK your actual Eclipse icon
- SELECT the "Show Contents" menu item.
- OPEN the "Contents/" folder
- OPEN the "MacOS/" folder
- OPEN "eclipse.ini" in a text editor.
- ABOVE the line that says "-vm" (without the quotes)
- ADD the line: -vm /System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin/java
This starts eclipse with Java 1.6, rather than the Java 1.7 that is now default on your system. Obviously, you need to re-start eclipse after editing it's .ini file.