I want to put method equals that returns true if two objects contains the same information inside the item.java
Ok, what is your question about how to write an equals() method?
The method needs to get a reference to another Item object and then compare each piece of information for for equality. If any are different you'd return false.
change the status into boolean to represent status
You currently have a variable name status that is a String. Is that what you are talking about?
You could use the three-way operator to set status's value depending on boolean_exp:
status = (boolean_exp ? "available" : "unavailable");