Java Programming - Language Fundamentals - Discussion

The most important feature of Java language is that it is Architecture Neutral. Earlier softwares were build for specific operating systems, Like softwares build for Windows They run only in windows not in other os like linux, unix, max etc. To resolve this A new language was introduced by Sunmicrosystems Known as Java and so many features were introduced in this language which makes it a powerful language.

System-is class of java.lang package.
Out-is static final method of System class. So it is called directly with class name.
(System.out).

And out is also reference of PrintStream class.
println-is method of PrintStream class in java.io package.

So it is called with reference of that class.
(System.out.println).

Hi All,

default values are given as follows:
Int------>0
String---> null
Dog (Object)------->null
Char -------------->"\u0000". it is hexa decimal representation of asii code of the chars. I think "\u0000" represents "space".
boolean------------> false.

Done.

Hi , in the given programe the dog is a object ,
which may any data type
the below programe illistreates

class Dv
{
int x;
}

class DefaultValues
{
public static void main(String str[])
{
Dv dog=new Dv();

int a[] = new int[5];
float b[] = new float[5];
double c[] = new double[5];
String d[] = new String[5];
char e[] = new char[5];
boolean f[] = new boolean[5];
System.out.println("Hi ,The Default Values: ");
System.out.println("For Object :"+dog.x);// here dog is object
System.out.println("Integer "+a[0]);
System.out.println("Float "+ b[0]);
System.out.println("Double " + c[0]);
System.out.println("String " + d[0]);
System.out.println("Character " + e[0]);
System.out.println("Boolean " + f[0]);
}
}

How can a char has a default value in terms of hexa-decimal?
Can any one clear?

That shows in hexa representation
java is same as c ,we can say this by this because java uses the syntax of c. for more advantages and comfortable they created java as platform independent

Integer 0.
Float 0. 0.
Double 0. 0.
String null.
Character has nothing as default value.

Is that Dog is a user define data type.
Or we can say that Dog is a object of a class.
class A
{
...
...
}
class B
{
A Dog=new A();
}

How we know the meaning of hexadecimal representation by looking?

Dog is not a primitive data type but you can define data types according to you in java. Here we are defining a class and its type is "Dog". I mean we have declare a Dog type class. Now when you create its object that is MyDog, it will contain "null" value.