Java Programming - Language Fundamentals - Discussion

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]);
}
}

Dear Sir,

1) Default value for array element of type char is nothing , not even null
2) Default value for array element of type float is 0.0 not 0.0f

class hello
{
public static void main(String str[])
{
int i[] = new int[5];
float f[] = new float[5];
double d[] = new double[5];
String s[] = new String[5];
char c[] = new char[5];
boolean b[] = new boolean[5];

System.out.println("Hello World");
System.out.println("Integer "+i[0]);
System.out.println("Float "+ f[0]);
System.out.println("Double " + d[0]);
System.out.println("String " + s[0]);
System.out.println("Character " + c[0]);
System.out.println("Boolean " + b[0]);
}
}

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 All,

Dog - There is no primitive datatype like 'Dog'. It is a User Defined type (a class created by User). By default it will hold null value.

For example:

public class Dog
{
//...
}

Dog myDog;

Here myDog will contain 'null' value by default.

Hope you understand. Have a nice day!

HI,
No where the "Dog" datatype is mentioned.
If Dog is integer , the default might be -0
If Dog is float , the default might be -0.0f
If Dog is object ,the default might be -null
.... No where it is mentioned whether Dog is wat datatype.
HELP ME IN THIS REGARD.....

why (3) is correct, as we don't know the data type of DOG so we can't say what will be the default that it may hold.

If DOG is any object then 'DOG -> null' will be ok but here we don't know anything about the word DOG so default value can't be assumed by words.

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.

Dog isn’t a built-in data type; it’s a reference type (a class).

But in Java, all reference types (including classes like Dog) have a default value of null when used as array elements or uninitialized variables.