Saraswat World

ASCII stands for American Standard code for Information Interchange. ASCII character range is 0 to 255.We can’t add more characters to the ASCII Character set. ASCII character set supports only English. That13is the reason, if we see C language we can write c language only in English we can’t write in otherlanguages because it uses […]

length() : In String class we have length() method which is used to return the number of characters instring.Ex : String str = “Hello World”;System.out.println(str.length());Str.length() will return 11 characters including space.length : we have length instance variable in arrays which will return the number of values or objects inarray.For example :String days[]={” Sun”,”Mon”,”wed”,”thu”,”fri”,”sat”};Will return 6 […]

A constructor is a special method used to initialize objects in java.we use constructors to initialize all variables in the class when an object is created. As and when an objectis created it is initialized automatically with the help of constructor in java.We have two types of constructorsDefault ConstructorParameterized ConstructorSignature : public classname(){}Signature : public […]

public : “public” is an access specifier which can be used outside the class. When main method is declaredpublic it means it can be used outside class.static : To call a method we require object. Sometimes it may be required to call a method without thehelp of object. Then we declare that method as static. […]

The process of wrapping or putting up of data in to a single unit class and keeps data safe from misuse is called encapsulation . Through encapsulation we can hide and protect the data stored in java objects. Java supports encapsulation through access control. There are four access control modifiers in java public , private, […]

It contains the executable body that can be applied to the specific object of the class.Method includes method name, parameters or arguments and return type and a body of executable code.Syntax : type methodName(Argument List){}ex : public float add(int a, int b, int c)methods can have multiple arguments. Separate with commas when we have multiple […]

Classes are fundamental or basic unit in Object Oriented Programming . A class is kind of blueprint or template for objects. Class defines variables, methods. A class tells what type of objects we are creating. For example take Department class tells us we can create department type objects. We can create any number of department […]

this() is used to access one constructor from another with in the same class while super() is used to access superclass constructor. Either this() or super() exists it must be the first statement in the constructor.

When a javac compiler compiler compiles a class it generates .class file. This .class file contains set of instructions called byte code. Byte code is a machine independent language and contains set of instructions which are to be executed only by JVM. JVM can understand this byte codes.

JIT compiler stands for Just in time compiler. JIT compiler compiles byte code in to executable code . JIT is a part of JVM . JIT cannot convert complete java program in to executable code it converts as and when it is needed during execution.

A class having two or more methods with same name but with different arguments then we say that those methods are overloaded.Static polymorphism is achieved in java using method overloading.Method overloading is used when we want the methods to perform similar tasks but with different inputs or values.When an overloaded method is invoked, java first […]

The most unique feature of java is platform independent. In any programming language source code is compiled in to executable code . This cannot be run across all platforms. When javac compiles a java program it generates an executable file called .class file. Class file contains byte codes. Byte codes are interpreted only by JVM’s […]

Abstract Class VS Interface Sr. Abstract Class Interface 1 Abstract class can contain abstract methods, concrete methods or both Interface contains only abstract methods 2 Except private we can have any access specifier for methods in abstract class. Access Specifiers for methods in interface must be public 3 Except private variables can have any access […]

Method Overloading VS Method Overriding Sr. Method Overloading Method Overriding 1 Method Overloading occurs within the same class Method Overriding occurs between two classes superclass and subclass 2 Since it involves with only one class inheritance is not involved. Since method overriding occurs between superclass and subclass inheritance is involved. 3 In overloading return type […]

Variables and methods of super class can be overridden in subclass . In case of overriding , a subclass object call its own variables and methods. Subclass cannot access the variables and methods of superclass because the overridden variables or methods hides the methods and variables of super class. But still java provides a way […]

If we have methods with same signature (same name, same signature, same return type) in super class and subclass then we say subclass method is overridden by superclass. When to use overriding in java If we want same method with different behavior in superclass and subclass then we go for overriding. When we call overridden […]

With in the same class if we want to call one constructor from other we use this() method. Based on the number of parameters we pass appropriate this() method is called. Restrictions for using this method : 1)this must be the first statement in the constructor 2)we cannot use two this() methods in the constructor

Static blocks or static initializers are used to initialize static fields in java. We declare static blocks when we want to initialize static fields in our class. Static blocks gets executed exactly once when the class is loaded. Static blocks are executed even before the constructors are executed

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