Having celebrated its 22nd anniversary in 2017, Java has professional consistent development in its programming efficiency for decades. It is one of the most popular programming languages around the world and is designed to keep running on any stage consistently.Java is the most commonly used programming language for the creation of web application and platform. It allows developers to write once, run anywhere(WOEA). It is general-purpose, a high-level programming language evolve by sun Micro system. at first known as an OAK, java source code documents are bundle into a format called BYTECODE which can keep running on any java virtual machine( JVM).The prevalent programming dialect java likes c++.
Today,it is the fastest, secure, and most dependable language of the computing platform.Therefore; here are the top reasons why java is the most popular programming Language.
There are several reasons why java is the most popular programming Language:-
- Platform independent:
One of the biggest reasons is platform independence; java lets developers “Write once, run anywhere”.It can be used to build end-to-end desktop or mobile applications that operates on different operating systems and server — from windows and Mac to linux and Unix,mainframes to mobile phones — making it a good choice for applications that need to be sun on several platforms. All it needs is a java runtime Environment (JRE).
2.Extreme scalability:
Being an all — round universal programming language , java offers extreme scalability, enabling developers to develop applications across the product spectrum — from mobile apps to large-scale industrial apps. Today, java is becoming the default programming language choice for building applications for the future-form natural language processing to loT and cloud development.
3.Easy to learn:
The foundational strength of java lies in the fact that it is easy to learn and run which is exactly why so many developers across the world develop programs on it . With such a short learning curve , when you write in java once ,you will learn syntax, patterns , tools and styles that can easily be used for other languages as well.
4. Object-oriented:
Java is fundamentally object-oriented ; the massive library of classes offers a world of commonly used utility functions, enabling developers to develop a range of programs and applications . What’s more, the modular structure makes defining data types, code can be reused and recycled and it is easy to maintain too.
5 . Open-source:
A Large number of open-source libraries and development tools make java a popular and economical choice for developing word-class applications. And with Google using java for android software development kits, it’s popularity is only exploding more.
6. User-friendly:
Unlike many programming languages that try to reinvent the wheel , java takes the best features from C and C++ (While ignoring the unnecessary and Unsuccessful ones) and adds more features and capabilities over time . As most developers are familiar with C and C++ , Java’s extreme syntax makes it easy for developers to build programs of any size and type.
7. Multi-functional:
Offering a pool of APLs and classes, java is perfect to build apps for every device: mobile phones, tablets,the web, and more. Although different OSes make use of different JVMs, the code across all of them is still predominantly java. In addition , many useful software and development tools are written in java.
8. Ever-growing community:
As more and more developments begin their development journey with java , the community is proving to be the pillar of the language . The ever-growing community of tens of thousands of developers that work on Java round-the-clock shere knowledge and insights and 0ffer feedback, help, and support.
Features of Java
1) Great performance
The java compiler is designed for performance. Java code is compiled into bytecode and then compiled by the java compiler. Post that , it is fed to the JVM(java virtual machine ) before it’s converted to machine code. Inspired by C and C++.C and C++ are long -tenured programming languages and they are ancestors of modern programming languages like Java and Python.
2) Multi- threaded
Multithreading capabilities construct right into the Java language . This means it is possible to build highly synergistic and responsive apps with a number of simultaneous threads of activity.
3) Platform Independence
Java has a philosophy called WORA (Writing Once , Run Anywhere).Java code is compiled into an intermediate format, called bytecode,which is to be executed in the JVM(Vava Virtual Machine ). Any system that runs a JVM is able to execute the Java code.
4)Truly Object -Oriented
Build open C++ which is semi object_oriented, Java extends the functionality to become a fully object — oriented programming language . Some of the most important features that make it an object — oriented purtian are:
● Abstraction
● Encapsulation
● Inheritance
● Polymorphism
5) Robust
Java guides the programmer to adopt important programming habits required for the creation of highly reliable applications. Unlike the management model reinforced by the automatic garbage collection feature.
6) sacure
Safety characteristic are built into the language and runtime systems. These comprise runtime checking and static type-checking at compile time. With such features in place, it becomes a formidable task to invade a java application from the outside.
7) Simple
simplicity of reading and writing makes any language simple. This holds true for java as it has a less equivocal syntax terminology. Anyone can start right off with java with an understanding of the basic fundamental principles of programming.
8)Other benefits of java
Other than the preceding features, here are some other great options for choosing java over other programming languages:
● A multitude of open-source libraries
● Backed by Oracle and high-level support forms tech giants like Google and IBM.
● Big and mature community support
● Several readily available frameworks for rapidly building reliable apps
● There are a galore of IDEs and tools to help make Java development simpler
All Basic Java Language constructs
In Java, these are the following language constructs
■ Data Types
■ Keywords
■ Literals
■ Methods
■ Operators
■ Control statements
■ Arrays
■ Identifiers
■ Comments
■ Loops
❏ Data types
Datatype tells the compiler, What kind of data can be assigned to a variable. A data type can be defined as a type that a variable can have.
It can be of two type
➔ Primitive data type
➔ Non-primitive data type
1. Primitive Data Types In Java
Java Primitive data types are the simplest types, i.e. they can’t have any
special capabilities and can have only single values.
There are eight primitive data types in Java-
A. Java boolean
It can represent only one bit of information , i.e. true or false . They cannot be changed either explicitly or implicitly, but the programs for conversion can be easily written.
Example:-
//A Java program to demonstrate boolean data type
Class boolean
{
Public static void main(String args[])
{
Boolean b=true;
if(b==true)
system.out.println(“true”);
}
}
B. Java byte
It is useful in saving memory for large arrays, it is a signed two’s complement integer. It has a size of 8 bits with a range from -128 to 127.
Example:-
//Java programming to demonstrate byte data type in Java
Class byte
{
Public static void main (String args[])
{
Byte a = 126;
System.out.println(a);
}
}
C. Java char
It is also a single character with a memory of 16 Bit Unicode characters. It has a range from ‘\u000’ or 0 to ‘\ufff’ or 65535.
Example:-
//Java program to demonstrate char data type in Java
Class short
{
Public static void main (String args[])
{
Char a = ‘G’;
System. Out. println(a);
{
}
D. Java short
Short is similar to byte and is used to save memory in large arrays . It is also a two’s complement with a size of 16 bit and ranges from -32,768 to 32,767 (inclusive).
Example:-
//Java program to demonstrate short data type in Java
Class short
{
Public static void main(String args [])
{
Short a = 56;
System.out.println(a);
}
}
E. Java int
Int is two’s complement with memory allocation of 32 bits and range from -2³¹ to 2³¹-1.
Example:-
//Java program to demonstrate int data type in Java
Class int
{
Public static void main (String args[])
{
Int a = 56;
System.out .println(a);
}
}
F. Java long
Long is two’s complement with memory allocation of 64 bits and range from -2⁶³ to 2⁶³-1.
Example:-
//Java program to demonstrate long data in Java
Class long
{
Public static void main (String args[])
{
Long a = 100000L;
System.out.println(a);
}
}
G. Java float
Float is a single-precision IEEE floating point with memory allocation of 32 bits and uses a suffix as F/f.
Example:-
//Java program to demonstrate float data type in Java
Class float
{
Public static void main ( String args[])
{
Float a = 4.5541132f;
System.out .println(a);
}
}
H.Java double
The double java data type is a default choice when it comes to decimal , as it is a double- precision 64 bit IEEE floating-point variable.
Example:-
//Java program to demonstrate double data type in Java
Class double
{
Public static void main (String args[])
{
Double a = 1.33526252726;
System. out.println(a);
}
}
2. Non primitive data types in Java
The non-primitive Java data types are manufacture by the programmer during the coding process, they are known as the “reference variables” or “object variables” as they refer to a location where data is stored.
a.Java string
Strings are fundamentally a collection of characters, they cannot change once they are created.
b.Java Array and object
An array in Java is a group of variables that are similar in nature and We can allocate them dynamically. Their size has to be specified in int, and their length can be found by member length. Their indexing always starts with zero.
❏ keywords
Java keywords are also known as reserved words . Keywords are specific words which act as a key to a code. There are preset word by java so it cannot be as variable or object name.
A list of java keyword or private words are given below:
1. abstract:Java abstract keyword is used to announce abstract class. Abstract class can provide the implementation of interfaces . It possess own
be in possession of command
count among one’s possessions enjoy grasp abstract and non-abstract methods.
2. Boolean: Java boolean keyword is used to announce a variable as a boolean type. It can grip True and False values only.
3. Break: Java split keyword is used to break loop[ or switch statement. It breaks the current flow of the program at identify condition.
4. Byte: Java byte keyword is used to announce a variable that can hold an 8-bit data value.
5. Case: Java case keyword is used with the switch statement to mark blocks of text.
6. Catch: Java catch keyword is used to catch the peculiarity generated by try statements. It will be used after the try block only.
7. Char: Java char keyword is used to announced a variable that can hold unsigned 16-bit unicode characters
8. Class: Java class keyword is used to declare a class.
9. Continue: Java pursue keyword is used to carry on the loop. It continues the current flow of the program and skips the last code at the specified condition.
10. Default: Java default keyword is used to specify the Levant block of code in a switch statement.
11. Do: Java do keyword is used in control statements to declare a loop. It can iterate a part of the program several times.
12. Double: Java double keyword is used to declare a variable that can hold a 16-bit floating-point number.
13. Else: Java else keyword is used to indicate the alternative branches in an if statement .
14. Enum : Java enum keyword is used to define a fixed set of constants . Enum constructor are always private or default.
15. Extends : Java extends keyword is used to indicate that a class is derived from another class or interface .
16. Final : Java final keyword is used to indicate that a variable holds a constant value. It is applied with a variable . It is used to restrict the user.
17. Finally : Java finally keywords indicate a block of code in a try-catch structure. This block is always executed whether an exception is handled or not .
18. Float : Java float keyword is used to declare a variable that can hold a 32 -bit floating-point number.
19. For : Java float keyword is used to start a for loop. It is used to execute a set of instructions/ functions repeatedly when some conditions become true . If the number of iterations is fixed . It is recommended to use a for loop.
20. If : Java if keyword tests the condition. It executes the if block if condition is true.
21. Implementation : Java implements keywords and is used to implement an interface.
22. Import : Java import keyword makes classes and interfaces available and accessible to the current source code.
23. Instanceof : Java instanceof keyword is used to test whether the object is an instance of the specified class or implements an interface.
24. Int : Java int keyword is used to declare a variable that can hold a 32-bit signed integer.
25. Interface : Java interface keyword is used to declare an interface . It can have only abstract methods.
26. Long : Java long keyword is used to declare a variable that can hold a 64-bit integer.
27. Native : Java native keyword is used to specify that a method is implemented in native code using JNI (Java Native Interface) .
28. New : Java new keyword is used to create new objects.
29. Null :Java null keyword is used to indicate that a reference does not refer to anything . It removes the garbage value.
30. Package :Java package keyword is used to declare a Java package that includes the classes.
31. Private :Java private keyword is an access modifier. It is used to indicate that a method or variable may be accessed only in the class in which it is declared.
32. Protected : Java protected keyword is an access modifier. It can be accessible within the package and outside the package but through inheritance only. It can’t be applied to the class.
33. public: Java public keyword is an access modifier. It is used to indicate that an item is accessible anywhere. It has the widest scope among all other modifiers.
34. return: Java return keyword is used to return from a method when its execution is complete
35. short: Java short keyword is used to declare a variable that can hold a 16-bit integer.
36. static: Java static keyword is used to indicate that a variable or method is a class method. The static keyword in Java is used for memory management mainly.
37. strictfp: Java strictfp is used to restrict the floating-point calculations to ensure portability.
38. super: Java super keyword is a reference variable that is used to refer to a parent class object. It can be used to invoke immediate parent class methods.
39. switch: The Java switch keyword contains a switch statement that executes code based on test value. The switch statement tests the equality of a variable against multiple values.
40. synchronized: Java synchronised keyword is used to specify the critical sections or methods in multi threaded code.
41. this: Java this keyword can be used to refer to the current object in a method or constructor.
42. throw: The Java throw keyword is used to explicitly throw an exception. The throw keyword is mainly used to throw custom exceptions. It is followed by an instance.
43. throws: The Java throws keyword is used to declare an exception. Checked exceptions can be propagated with throws.
44. transient: Java transient keyword is used in serialization. If you define any data member as transient, it will not be serialized.
45. try: Java try keyword is used to start a block of code that will be tested for exceptions. The try block must be followed by either catch or finally block.
46. void: Java void keyword is used to specify that a method does not have a return value.
47. volatile: Java volatile keyword is used to indicate that a variable may change asynchronously.
48. while: Java while keyword is used to start a while loop. This loop iterates a part of the program several times. If the number of iterations is not fixed, it is recommended to use a while loop.
■ Literals
A literal is a source code representation of a fixed value. They are represented directly in the code without any computation.
Literals can be assigned to any primitive type variable.
Example
byte a = 68;
char a = 'A'
■ Methods
A method is a block of code which only runs when it is called.
You can pass data, known as parameters, into a method.
Methods are used to perform certain actions, and they are also known as functions.Why use methods? To reuse code: define the code once, and use it many times.
■ Operators
Java provides a rich set of operators to manipulate variables. We can divide all the Java operators into the following groups −
- Arithmetic Operators
- Relational Operators
- Bitwise Operators
- Logical Operators
- Assignment Operators
- Misc Operators
■ Control statements
Decision Making in programming is similar to decision making in real life. In programming also we face some situations where we want a certain block of code to be executed when some condition is fulfilled.
A programming language uses control statements to control the flow of execution of program based on certain conditions. These are used to cause the flow of execution to advance and branch based on changes to the state of a program.
Java’s Selection statements:
- if
- if-else
- nested-if
- if-else-if
- switch-case
- jump — break, continue, return
■ Arrays
An array is a group of like-typed variables that are referred to by a common name.Arrays in Java work differently than they do in C/C++. Following are some important point about Java arrays.
- In Java all arrays are dynamically allocated.(discussed below)
- Since arrays are objects in Java, we can find their length using member length. This is different from C/C++ where we find length using sizeof.
- A Java array variable can also be declared like other variables with [] after the data type.
- The variables in the array are ordered and each have an index beginning from 0.
- Java array can be also be used as a static field, a local variable or a method parameter.
- The size of an array must be specified by an int value and not long or short.
- The direct superclass of an array type is Object.
- Every array type implements the interfaces clonable and java.io.Serializable.
Array can contains primitives (int, char, etc) as well as object (or non-primitives) references of a class depending on the definition of array. In case of primitives data types, the actual values are stored in contiguous memory locations. In case of objects of a class,the actual objects are stored in heap segment.
■ Identifiers
In programming languages, identifiers are used for identification purpose. In Java, an identifier can be a class name, method name, variable name or a label. For example :
public class Test
{
public static void main(String[] args)
{
int a = 20;
}
}In the above java code, we have 5 identifiers namely :
- Test : class name.
- main : method name.
- String : predefined class name.
- args : variable name.
- a : variable name.
■ Comments
Comments can be used to explain Java code, and to make it more readable. It can also be used to prevent execution when testing alternative code. Single-line comments start with two forward slashes ( // ). Any text between // and the end of the line is ignored by Java (will not be executed).
■ Loops
In programming languages, loops are used to execute a set of instructions/functions repeatedly when some conditions become true. There are three types of loops in Java.
- for loop
- while loop
- do-while loop
That’s All!
Whether you’re looking forward to a career in game development or develop clean web applications, Java is worth the effort. The programming language is able to convert to a wide set of environments, thus allowing for remarkable ability and opportunities.
Learning Java allows you to better understand the primary concepts of programming as well as enable you to have a jump start in learning other popular, Java-inspired programming languages.
For a web developer, there are several programming languages and frameworks to toy with. Therefore, the more the merrier. Having an understanding of several web technologies and programming languages will ensure you stay relevant in the rapidly-evolving field of IT and make a good living in the age of information.
