This error was coming whenever i write my minecraft code... I just watched Mr. Pineapple's Modding tutorial for minecraft 1.15 and i followed as he told. Is it because of that i'm coding for 1.16 and the tutorial is for 1.15? or just something else? Here's the screen shot:

The errors are highlighted in yellow... if anything is wrong tell resp asap

Thanks in advance! 

Simple answer: yes, things changed from 1.15 -> 1.16, that method probably has a different name now (don't know what it is because I do not have a workspace setup currently). If you poke around in the Item class, you can probably find what it was changed to by looking at the type of the method parameters.

If you are not decently familiar with Java, I would suggest learning more basic Java before trying to write a mod, you will be running into problems like this a lot if you do not.