Java, General-purpose Programming Language

Java is a general purpose programming Language. James Gosling, Mike Sheridan, and Patrick Naughton initiated the Java language project in June 1991. This was initially called "Oak", which was renamed as "Java" in 1995. The development motive of java was to make a platform independent language that can create create softwares that can be embedded in various consumer electronic devices.

General Purpose Programming Language

A general-purpose language is a computer language that is broadly applicable across application domains, and lacks specialized features for a particular domain. This is in contrast to a domain-specific language (DSL), which is specialized to a particular application domain.

Features of java

• Simple
• Object-Oriented
• Robust
• Multihreaded
• Architecture-Neutral
• interpreted and High Performance
• Distributed
• Dynamic
• Secure
• Portable

Learn more about java at Get Started with Java Programming Language.

A Simple java Program:

class JavaFirst {     public static void main(String args[])     {         System.out.println("Hello World!");     } }

Java Keywords

abstract	final	public
assert	finally	return
boolean	float	short
break	for	static
byte	goto	strictfp
case	if	super
catch	implements	switch
char	import	synchronized
class	instanceof	this
const	int	throw
continue	interface	throws
default	long	transient
do	native	true
double	new	try
else	null	void
enum	package	volitile
extends	private	while
false	protected

Enhanced For Loop in Java

Enhanced loop was introduced on java 5. It is used to loop through the Arrays.

class LoopTest

{

    public static void main(String args[])

    {

         int numbers[]={10,11,12,13,14};

         for (int i : numbers)

         {

              System.out.println(i);

          }

     }

}

The Output of the Loop will be:
10
11
12
13
14

Array Declaration in Java

int [] a, b, c;

will create 3 arrays a, b and c

int a[], b ,c[];

will create 2 arrays a and c, where as a int variable b.

If we use the [] in front it will create all the variables as array.

Strings

In java String are not simply an array of characters. String is defined as objects. String are used to declare String variables. String objects have many special features and attributes that make them powerful.

.toUpperCase()

.toLowerCase()

.compareTo()

.indexOf()

.charAt()

The Bitwise Operators

Java defines several bit-wise operators which  can be applied to the integers, long, short, char and byte. Bit-wise operator works on bits and perform bit by bit operations.

Where a = 60 and b = 13

a = 0011 1100

b = 0000 1101

(Binary AND) a&b = 0000 1100

(Binary OR) a|b = 0011 110.1

(Binary XOR) a^b = 0011 0001

(Binary NOT) ~a = 1100 0011

Argument Passing

Call by Value and Call by Reference

When a primitive type is passed to a method, it is done by use of call-by-value. Object are implicitly passed by use of call-by-reference.