At the time of this writing, there is no official release of Java SE 7 / Oracle JDK 1.7 on Mac OS X. It is still in developer preview based on Apple’s contributions to OpenJDK. The Developer Preview is provided to the community so that the developers can get feedback on the ongoing progress of the project. The developer preview should work on any Intel-based Mac and has been tested on Mac OS X 10.6.8 (Snow Leopard) and 10.7 (Lion).
Download Java for OS X directly from Oracle. Get the latest version If an app or webpage you want to use asks you to install Java software, you can download the current version of Java for OS X directly from Oracle's website. With Mac OS 10.7 (Lion) and later, the Java runtime is no longer installed automatically as part of the OS installation. Follow any of the methods below to install Java runtime.
UPDATE
Oracle has launched the official Java SE 7 for Mac OS X 64-bit platform. You can download it from here.
This tutorial shows you how to install Java SE 7 Developer Preview on Mac OS X 10.7.2 Lion running on my MacBook Pro.
1. Download the Oracle JDK7 Mac OS X port dmg file from here. At the time of this writing, the version of the JDK7 is Oracle JDK7 build b223 released on December 23, 2011. The dmg file name is jdk-7-ea-macosx-b223.dmg
2. Create a JavaVirtualMachines folder under /Library/Java if it doesn’t exist.
In my case, the JavaVirtualMachines is already there so I don’t need to create it manually.
3. Open the jdk-7-ea-macosx-b223.dmg file by double-clicking on it. Then drag the JDK 1.7.0 Developer Preview icon in the left side to the JavaVirtualMachines icon folder in the right side.
4. Go to /Library/Java/JavaVirtualMachines directory using Finder application. Then double-click the ‘JDK 1.7.0 Developer Preview’ icon. This will open the Java Preferences window. Here you can change the preferred order of the installed Java platforms by dragging it up or down. Make sure the Java SE 7 is in the preferred order or you can simply deselect the Java SE 6 version.
5. Now issue the ‘java -version’ command in the terminal window to verify.
6. Done
While launching, Dreamweaver (13.2 and earlier versions) prompts you to install Java SE 6 Runtime.
Java SE 6/SE 7 Runtime is installed on the computer.
Note:
In Dreamweaver 2014, the prompt does not appear when you launch Dreamweaver. However, you are prompted to install Java SE 6 runtime while logging in to PhoneGap Build service (Site > PhoneGap Build Service > PhoneGap Build Service).
In the pop-up window that appears, click Install and follow the onscreen instructions to install Java SE 6 Runtime.
Note:
In Dreamweaver 2014, you can't log in to PhoneGap Build service without installing Java SE 6 Runtime.
Important: Ensure that you install Java SE 6 Runtime only by clicking Install in the pop-up window. If you install Java SE 6 or 7 Runtime through any other means (for example, by directly accessing Java.com), Dreamweaver could still display the prompt.
Download Java Se 6 Mac Os X 10.6
Even if you have installed Java SE 7 Runtime, you still need to install Java SE 6 Runtime as described above.
If you continue to see the prompt even after installing Java SE 6 Runtime as described above, perform the following steps:
Download Java Se 6 Mac Os X 10.10
Dreamweaver displays such a prompt because, when you update to Mac OS 10.9, Java SE 6 Runtime on your computer gets uninstalled.