I've installed the 1.7.2 forge setup on Mac (And I am currently on a Mac so you're in luck). Follow Each step and if you have any questions, quote the specific step, not the whole post.
Step 1: If you tried to download files before this and failed, delete all the files you downloaded and created and start fresh and new.
Step 2: Go to the files Forge Website[Click Here!] and download the recommended (or latest if you want) 1.7.2 src. Like So:
Step 3: After you finish downloading that, you should get something similar to the first picture below. Open up Terminal and type in "cd [the directory that the gradlew file is in]" then hit Return. After that, the directory on the left side will change, after that type in"bash [drag the gradlew file to the screen]" and click Return again. It will show something line the second picture below.
Step 4: It will download a bunch of files and when it's done downloading, You should see this below:
Step 5: Type in the command: "bash gradlew setupDecompWorkspace" and hit Return. After that's done setting up, run "bash gradlew eclipse", then Return. After that, type in "bash gradlew setupDecompWorkspace" again, because of the forge src. Then when thats done, If you want to be sure, you could run that same command again. Just to be sure, I would recommend it.
Step 6: Open up Eclipse and point to the "eclipse" folder in the downloaded forge folder. When eclipse starts up and opens, You could see the example code, they gave, and all other dependencies. In the dependancies you could see the jar file "forge-src". If you open that up, you'll see all the Minecraft code!
Let me know if there were any problems, or if I did something wrong. I will fix it right away!
This might be a problem from a previously downloaded file, Did you try downloading this all before? If so, delete all the files that were downloaded and completely restart. To delete the .gradle file in your user home directory, you might have to enable hidden files to delete it. This is what I would do. I also see that is says (Permission denied) so that's why It might have to be deleted and restarted all again. May I also see some of your Mac Specs? If you're comfortable with it, Of course.
Unless, the actual program doesn't start, let me know. If not: this will have to do with actual minecraft and actual modding, try posting a new thread with this whole report. in it's corresponding topic. Thanks!
You will have to enable showing hidden files. To do so, follow this tutorial. Once you have hidden files show on your Mac, (to make sure, go to your desktop and you'll see the .DS_Store and .localized files there, if not, you might not have done it right) you go to this directory: "/Users/owner/.gradlew" Delete that directory, and redo the whole setup. If this doesn't work, let me know. It might be something personal! I'd love to help you out with!
From the line Java heap space, I would have to guess that Java ran out of memory. This means that not enough memory is being allocated to program. Search online for Java heap space and see any solutions you can come up with.