That specifier means that they can be accessed only by the methods of the same class, not by any other method.
Ex. private int value
Ex. public int value
Instance Variables
Instance variables store the data required for executing its methods.
Instance variables should always be private.
Ex. private int value;
Ex. private double change;
Parameter Vairables
The variable that holds the argument.
Ex. int value = cash.getValue(parameterVariable)
Public
The word public denotes that the class is usable by the “public."
Private
Details hidden from the programmers who use objects and call methods.
Encapsulation
Encapsulation is the process of hiding implementation details and providing methods for data access.
Void
When a method returns no value.
Local Variable
A local variable is a variable that is declared in the body of a method.
Null
The null reference refers to no object.
Ex. Note that the null reference is not the same as the empty string "". The empty string is a valid string of length 0, whereas a null indicates that a string variable refers to no string at all.
Explicit Parameters
All other parameter variables (such as the # int the getNumFields method) are called explicit parameters.
Ex. plot2.getNumFields(400);
Implicit Parameter
When you implement the method, you provide a parameter variable for each arguement. But you don’t need to provide a parameter variable for the object on which the method is being invoked.
This
The 'this' reference denotes the implicit parameter.