Parameters, also known as formal parameters, are variables declared in the method signature. They act as placeholders for the values that will be passed. They are local to the method.
Arguments, also known as actual parameters, are the actual values passed to the method when it is invoked. They must match the parameter type and order.
Parameter passing mechanisms in Java include pass by value for primitive types and pass by reference value for objects. Changes to primitive types inside a method do not affect the original variable, while changes to an object's state are reflected outside the method.
Variable-length arguments, known as varargs, allow a method to accept any number of arguments of the same type. They are defined using the syntax 'Type... variableName'.