Java Questions

Anonymous class is class without name.

EX:

class A {

}

class Demo {

    A r = new A() {

        }; //anonymous class

}

The JVM performs three main tasks:

• Loads code

• Verifies code

• Executes code

These are accessibility modifiers. Private is the most restrictive, while public is the least restrictive. There is no real difference between protected and the default type (also known as package protected) within the context of the same package, however the protected keyword allows visibility to a derived class in a different package.

Overriding is a method with the same name and arguments as in a parent, whereas overloading is the same method name but different arguments

Non-static member class is a class defined inside outer class with out static modifier.

EX:

class A { // top level class or outer class

    ......

    class B { //non-static member class

    }

    .....

}

The JDBC Driver provides vendor-specific implementations of the abstract classes provided by the JDBC API. This driver is used to connect to the database.

String class objects are immutable objects and they represents strings( sequence of characters)

StringBuffer class objects are mutable objects representing strings and they are Thread safe

StringBuild class objects are also mutable objects representing strings and they are not Thread safe

Package is a collection of related classes and interfaces. package declaration should be first statement in a java class.