Java Notes

The keyword “extends” signifies that the properties of super class are extended to the subclass. That means, subclass contains its own members as well of those of the super class.

A class represents a set of objects that share common characteristics and behavior. An object is an identifiable entity with some characteristics and behavior.

The Java Programs need to be written just once which can be run on different platforms without making changes in the Java program. Only the Java interpreter is changed depending upon the platform.

Token – The smallest individual unit in a program is known as Token. There are five tokens in Java.

Constructor is a member function with the same name as that of a class and is used to initialize the data members of the class with a legal initial value.

In other words, a wrapper class wraps a value of primitive type in an object.

int indexOf(char/String) – returns the index of the first occurrence of the specified character /string in the current string object. If the character/String is not present, it returns -1

A Scanner class breaks its input into tokens using a delimiter pattern, which by default matches white space. The resulting tokens may then be converted into values of different types using the various next methods.