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Explain why a class might provide a set method and a get method for an instance variable?
A class might provide a set method (setter) and a get method (getter) for an instance variable in order to encapsulate the internal implementation of the class, and to isolate that implementation from the public interface of the class.
Even if the setter and getter does no more than directly set and get the instance variable, the public interface should use that paradigm in order to allow for possible future alteration of the implementation, while minimizing the impact of doing so.
Proper OOD/P (Object Oriented Design/Programming) should always make the implementation be private, even for derived classes. This reduces error, and reduces "lazy" coding techniques.
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What is Variable Shadowing in Java?
In Java, there are three kinds of variables: local variables, instance variables, and class variables. Variables have their scopes. Different kinds of variables have different scopes. A variable is shadowed if there is another variable with the same name that is closer in scope. In other words, referring to the variable by name will use the one closest in scope, the one in the outer scope is shadowed.A Local Variable Shadows An Instance VariableInside a class method, when a local variable have the same name as one of the instance variable, the local variable shadows the instance variable inside the method block.
What is the difference between static and nonstatic member with example in java?
It depends on whether the member is a static variable or a static method of the class.A non-static member variable is an instance variable. That is, each instance of the class has its own independent set of instance variables.A static member variable is not associated with any one instance of the class, and exists even when there are no instances of the class. As with all static variables, it exists for the entire duration of the program.A non-static member method is an instance method, thus the method automatically inherits a this pointer.A static member method does not inherit a this pointer, but it does have private access to to the class. Thus specific instances can be passed to a static method if necessary.Static members can be thought of as being common to all instances of a class, rather than a specific instance, even though no instances are actually required in order to make use of them.
What is mean by instance variable with example?
hi friend.... Instance variable means with which you need to create an obeject in order to invoke any methods or variables defined in a class. For ex: class A { int a=10; public void inc() {return a++; } } To invoke a member A b=new A(); b.inc(); System.out.println(b.a); If incase of a static method you can directly call using class name itself. like : b=Math.sqrt(a);
What does a Java Boolean type variable declared but not yet initialized contain when its class is instanciated?
If it is a class or instance variable, it gets the default value of false. If it is a local variable (inside a method), it doesn't have a value until you explicitly set one.
A variable that is declared inside a method is called variable?
It is called a local variable since it only exists inside the method.
What is Variable Shadowing in Java?
In Java, there are three kinds of variables: local variables, instance variables, and class variables. Variables have their scopes. Different kinds of variables have different scopes. A variable is shadowed if there is another variable with the same name that is closer in scope. In other words, referring to the variable by name will use the one closest in scope, the one in the outer scope is shadowed.A Local Variable Shadows An Instance VariableInside a class method, when a local variable have the same name as one of the instance variable, the local variable shadows the instance variable inside the method block.
What is the difference between variable declared inside the declaration part and variable declared in scriptlet part?
Variable declared inside declaration part is treated as a global variable, which means after translation of jsp file into servletthat variable will be declared outside the service method as an instance variablethe scope is available to the complete jspVariable declared inside a scriplet will be declared inside a service method as a local variable and the scope is with in the service method.
What is the difference between static and nonstatic member with example in java?
It depends on whether the member is a static variable or a static method of the class.A non-static member variable is an instance variable. That is, each instance of the class has its own independent set of instance variables.A static member variable is not associated with any one instance of the class, and exists even when there are no instances of the class. As with all static variables, it exists for the entire duration of the program.A non-static member method is an instance method, thus the method automatically inherits a this pointer.A static member method does not inherit a this pointer, but it does have private access to to the class. Thus specific instances can be passed to a static method if necessary.Static members can be thought of as being common to all instances of a class, rather than a specific instance, even though no instances are actually required in order to make use of them.
what is the difference between final and static keywords?
static: we can use the keyword static either to method or to a variable. when we declare to a method,(eg: public static void main(String args[]),we can use this method without any object. when we use to a variable,there will be only one instance of that variable irrespective of how many objects that get created of that class. Final: Usage of final to method or to a variable makes them as constant. It's value cannot be changed...
What is mean by instance variable with example?
hi friend.... Instance variable means with which you need to create an obeject in order to invoke any methods or variables defined in a class. For ex: class A { int a=10; public void inc() {return a++; } } To invoke a member A b=new A(); b.inc(); System.out.println(b.a); If incase of a static method you can directly call using class name itself. like : b=Math.sqrt(a);
What does a Java Boolean type variable declared but not yet initialized contain when its class is instanciated?
If it is a class or instance variable, it gets the default value of false. If it is a local variable (inside a method), it doesn't have a value until you explicitly set one.
What are variable of the scientific method?
what are the variable
Explain different types of coding style in software engineering?
Meaningful variable names. Always use descriptive and meaningful variable names. Don't worry about the length. Meaningful variable names help other people reading your code understand what is going on. Example: if (a <= = 24) What is a? This is confusing. if (vacationHours <= = 24) See, better. <li>Variable scope indicated by name. Code is easier to read and understand if each variable indicates it's scope. One way to do this is to add prefixes to variable names, for example: Scope = Class member or instance variable: m_hours Scope = Class static variable: s_hours Scope = Parameter passed in a method call: p_hours Scope = local variable to a method: l_hours Regards ~Anoop
A variable that is declared inside a method is called variable?
It is called a local variable since it only exists inside the method.
How do you call a method from inside the main method?
I assume the question is about Java. How you call a method from inside the main method depends on whether this is an instance method or a static method. To call an instance method, you need to have a valid instance. Say foo is an instance of class Foo, which was created inside the main method. Then to call the instance method implode() use foo.implode() To call the static method bar() of class Foo, use Foo.bar().
What are the 6 ways to use this keyword?
"Java This keyword" is a reference to the current object, it is very helpful when you need to refer an instance of a particular Object from its available methods or using it's constructor, also "this" keyword helps us to avoid naming conflicts.The following are different ways to use java this keyword1) Using with instance variable2) Using with Constructor3) Pass / Return current instanceUsing with instance variableUsing this keyword inside a method or constructor it will use instance variable instead of local variable, in the absence of this keyword it will use local variableUsing with instance variableUsing this keyword inside a method or constructor it will use instance variable instead of local variable, in the absence of this keyword it will use local variableUsing with ConstructorUsing this keyword inside constructor like followingthis("Sony", 20); it will call the constructor having same parameter
It is perfectly legal to any instance variable inside of a static method?
No. You will get compilation errors. The complier will complain that you are trying to access non static variables from inside a static method. A static method can access only static variables.
