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abstract method
subject			fact

abstract method	has definition A method with no implementation
	does not have part body
	has purpose to serve as a placeholder, indicating that subclasses must have concrete implementations
	is a subtopic of Methods
	is always overridden by a method in a subclass
	is created by marking it abstract
	is a kind of instance method
	may not be defined in a class that is not abstract
	must have overriding methods in all non-abstract subclasses with instances that call that method
	must not contain any executable statements in its body
instance method	can operate on the current object's instance variables
	can refer to the object itself using the 'this' keyword
	has access to every class variable of its class
	has example public float credit(float amountToCredit) { balance = balance + amountToCredit; return balance; }
	implements the behaviour of the objects in the class
	is part of a class
	may be declared public, protected or private
	should be placed in a class such that there is no needless duplication of it, and such that it is useful in all the subclasses of the class in which it is defined
method	if a method is declared with the same method signature as a method in a superclass then this method overrides the method with the same method signature in the superclass
	if a method may throw a checked expression then the method must have a throws clause that mentions the class of that exception or one of the superclasses of the class of that exception
	when a method is called a piece of memory is allocated for every parameter
	when a method is called and the method's parameter is a reference type then the memory allocated for that parameter holds a copy of the address of the argument
	when a method is called and the method's parameter is a primitive type then the memory allocated for that parameter holds a copy of the parameter itself
	belongs to a class
	can access all instance variables of all objects of its class
	can be inherited by subclasses of its class
	can be accessed by other methods and variables in any class in the same package by default
	can use the super method to invoke a method declared in the superclass
	cannot be passed as an argument to a method or constructor
	creates an object by instantiating a class
	does not return a value if it has a void return type
	has part a block of implementation code
	is equivalent to the terms "function member" or "member function" which are used in C++
	is equivalent to the terms "routine", "function" or "method" which are used in non object-oriented programming languages
	may have access modifier public or private or protected
	overrides a method in a superclass with the same name
	returns a value that is of the return type of the method or a subtype of that type
	should be as private as possible
	should not be public except for those that will definitely need to be called from outside the package
	should return to its caller from only one place which should be the last statement
	usually hides instance variables, class variables from other objects
access unit	has access mode
syntactic unit	has syntax rule bold = mandatory italic = non-terminal normal font = optional

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