Java programming calculator

I had to make a calculator using stacks. Here is what i have so far. For some reason, the equal sign doesn't work. Can someone help me fix this. The code shows no error,
http://pastebin.com/SjemnE0V

>>1 posts a link to miserable pile of spaghetti.
>>2 suggests adding tumors.
>>3 tells >>1,2 to go back to /b/, please.