I'm creating a Java code and keep getting this error >

TestClass.java:26: error: non-static method isEmpty(LetterInventory) cannot be referenced from a static context

I have code from 2 separate Java files that are conflicting.

For the first file, LetterInventory, it compiles without issue. I have:

public int size() {       return size;    } // end size    // If Letter Inventory is empty, returns true.  // If Letter Inventory is not empty, returns false.    public boolean isEmpty(LetterInventory p) {       if(size == 0) {          return true;       }       return false;

The 2nd file, TestClass, is the one giving me the error:

String insert = scan.next();       LetterInventory v = new LetterInventory(insert);       if(LetterInventory.isEmpty(v)) {

There are a few more pieces of code surrounding it, but it's mostly println's, so I don't think it has anything to do with it.

Please help! If you could also give an example of what would work in the code, that would be amazin.g