3: Create a new folder called MCP on your desktop.
4: Extract the MCP zip contents to the MCP folder on your desktop.
5: Create a new folder on your desktop called Eclipse.
6: Extract the Eclipse zip to the Eclipse folder on your desktop.
Assuming you have modded before, I assume you know where your Minecraft folder is. If not please Google it.
7: Run Minecraft and force update it.
8: Once you finish force updating Minecraft open the MCP folder on your desktop and goto the jars folder.
9: Now locate your Minecraft bin folder and resource folder and copy them into the jars folder in your MCP folder on your desktop.
10: go back into the main MCP folder and click the decompile.bat or if on Mac OS X the decompile.sh
Wait for it to decompile, it may take a while.
11: Once it is done decompiling close your MCP folder and open your Eclipse folder on your desktop and run Eclipse.
12: Eclipse should ask you to locate your workspace, Click browse and locate your MCP folder, and look for the Eclipse folder inside the MCP folder on your desktop.
13: Select the Eclipse folder (Do not open it just select it and click OK)
14: Press OK in the Eclipse workspace selection window and it should set everything up and open.
[Modding the file]
1: In Eclipse there should be a package explorer tab on the left side.
2: Click the arrow beside Client and then click the arrow beside src.
3: From here scroll down to net.minecraft.src and click the arrow beside it.
4: In net.minecraft.src scroll down until you find EntityArrow.java.
5: Double click on EntityArrow.java.
6: Now in the editor (Center of the Eclipse window) you should see alot of code, press ctrl+F or on Mac OS X command+F.
7: in the find/replace window type ++this.ticksInGround in the find text box.
8: Now under the line of code ++this.ticksInGround copy and paste the code below or type it exactly as shown including capital letters.