Saraswat World

Finally block in java-Finally block is used for cleaning up of resources such as closing connections, sockets etc. if try blockexecutes with no exceptions then finally is called after try block without executing catch block. If there isexception thrown in try block finally block executes immediately after catch block.If an exception is thrown, finally block […]

In some cases our code may throw more than one exception. In such case we can specify two or morecatch clauses, each catch handling different type of exception. When an exception is thrown jvm checkseach catch statement in order and the first one which matches the type of exception is execution andremaining catch blocks are […]

Each try block requires atleast one catch block or finally block. A try block without catch or finally, will result in compiler error. We can skip either of catch or finally block but not both.

try and catch keywords in java- In try block we define all exception causing code. In java try and catch forms a unit. A catch block catches the exception thrown by preceding try block. Catch block cannot catch an exception thrown by another try block. If there is no exception causing code in our program […]

List of five keywords related to Exception handling in Java1) Try2) Catch3) throw4) throws5) finally

We can handle exceptions in either of the two ways :1) By specifying try catch block where we can catch the exception.2) Declaring a method with throws clause .

1) Separating normal code from exception handling code to avoid abnormal termination of program.2) Categorizing in to different types of Exceptions so that rather than handling all exceptions withException root class we can handle with specific exceptions. It is recommended to handle exceptions withspecific Exception instead of handling with Exception root class.3) Call stack mechanism […]

Error is the subclass of Throwable class in java. When errors are caused by our program we call that as Exception, but some times exceptions are caused due to some environment issues such as running out of memory. In such cases we can’t handle the exceptions. Exceptions which cannot be recovered are called as errors […]

Exception handling is a mechanism what to do when some abnormal situation arises in program. When an exception is raised in program it leads to termination of program when it is not handled properly. The significance of exception handling comes here in order not to terminate a program abruptly and to continue with the rest […]

1) Accessing an element that does not exist in array.2) Invalid conversion of number to string and string to number.(NumberFormatException)3) Invalid casting of class(Class cast Exception)4) Trying to create object for interface or abstract class(Instantiation Exception)

In java exception is an object. Exceptions are created when an abnormal situations arise in our program. Exceptions can be created by JVM or by our application code. All Exception classes are defined in java.lang. In otherwords we can say Exception as run time error.

An abstract method is the method which doesn’t have any body. Abstract method is declared with keyword abstract and semicolon in place of method body. Signature : public abstract void <method_name>(); Ex : public abstract void getDetails(); It is the responsibility of subclass to provide implementation to abstract method defined in abstract class.

We can create constructor in abstract class , it doesn’t give any compilation error. But when we cannot instantiate class there is no use in creating a constructor for abstract class.

Sometimes we may come across a situation where we cannot provide implementation to all the methods in a class. We want to leave the implementation to a class that extends it. In such case we declare a class as abstract. To make a class abstract we use key word abstract. Any class that contains one […]

final access modifier can be used for class, method and variables. The main advantage of final access modifier is security no one can modify our classes, variables and methods. The main disadvantage of final access modifier is we cannot implement oops concepts in java. Ex : Inheritance, polymorphism. final class : A final class cannot […]

We can use all access modifiers public, private, protected and default for variables.public : When a variables is declared as public it can be accessed1) In the same class2) In the same package subclass3) In the same package non subclass4) In the different package subclass5) In the different package non subclass. default : When a […]

We can use all access modifiers public, private, protected and default for methods.public : When a method is declared as public it can be accessed1) In the same class2) In the same package subclass3) In the same package non subclass4) In the different package subclass5) In the different package non subclass. default : When a […]

We can use only two access modifiers for class public and default.public: A class with public modifier can be visible1) In the same class2) In the same package subclass3) In the same package nonsubclass4) In the different package subclass5) In the different package non subclass.default : A class with default modifier can be accesed1) In […]

In C++ we have access specifiers as public, private, protected and default and access modifiers as static, final. But there is no such division of access specifiers and access modifiers in java. In Java we have access modifiers and non access modifiers. Access Modifiers : public, private, protected, default Non Access Modifiers : abstract, final, […]

The important feature of encapsulation is access control. By preventing access control we can misuse of class, methods and members. A class, method or variable can be accessed is determined by the access modifier. There are three types of access modifiers in java. public, private, protected. If no access modifier is specified then it has […]