Final Modifiers

The final modifiers

Final modifier is very versatile

  • When the final modifier is applied to any class, it means that the class cannot be subclassed
  • When it is applied to any variable, it means that the variable is constant.
  • When it is applied to any method, it means that the method cannot overridden by sub classes.

Criteria for a Good Program

Good is a subjective criteria and denotes situation whereby a program can completely meet with all the user specifications and run without error under all given circumstances. Good programming is the practice of constructing and implementing quality programs within an acceptable time span. Once the program is written, they are used in their operating environment for a period which may span ten or more years .During this period of time, programs will be subject to any alternations or enhancements to reflect changing needs of users.

Tokens

A program is a set of instructions to be executed by the computer to accomplish a particular task. While writing a program one has to take care of data which the program will process and generate information.

Data Types

 Before we talk about data type first we know about variable because data type is used with variable. Without variable the meaning of the data type is nothing, it's incomplete. Data types are used when you create variable in the program. Each variable is assigned a data type.

 

Variable

Variable is the name of the memory location from which we store the value .This is clear in above example.A name that holds a value.We can use variable to represents data.

Java Virtual Machine

     JVM is a virtual machine that act as an interpreter between java byte code and a computer’s operating system.By using JVM we can run java code on any platform.A JVM include a JIT(just-in-time)compiler within it.JIT compiler converts whole program to bytecodes . JVM recognizes a particular format of a file called “class file(extension.class)”. Each "class file(extension .class)" contains the definition of a single class or interface.

 

Difference between C C++ and Java

WHAT IS THE DIFFERENCE BETWEEN C C++ JAVA

1)Language->C is a procedural language,c++ is a object oriented language .Java is a pure object oriented language.

2)Header Files->In C we use stdio.h header file .In C++ we use iostream.h,conio.h headerfile but Java does not support any header files.

Access Modifiers in Java

ACCESS MODIFIERS…….

Access modifier is a reserve keyword or we can say visibility controls which is used to restrict access.We can use these access modifier to determine whether a fields or methods in a class ,can be called or used by another class or sub class or not.That means these access modifiers can prevent unauthorized updation or execution of fields and methods of the particular object.

 

Features of Java

COMPILED AND INTERPRETED:  

       In a computer language either compiler or interpreter is used. But in Java both are used .The Java compiler translates source code into bytecode. Bytecodes are not machine codes after compiles the program Java interpreter generates machine codes that can be executed or running the program that is why we can say that Java compiled and interpreted. These two steps provide security.

Introduction to Java

Java is an object oriented programming language which was developed by James Gosling at Sun Micro System in 1991 and released in 1995.The original name of Java called OAK. Java was designed for the development of electronics devices like TVs, Machines etc.

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