Practical 1st : Demo of primitive types in java

Practical code to understand the Primitive types in java, to know theoretical part follow my post here,Basic Java Fundamentals

package in.technoscience;

class hello {
 byte b;        
 short s;          
  int i;
 long l;
 float f;
  double d;
  char ch;
  boolean b1;
  float f1 = 10.9f;
 

 void show1() {
  System.out.println("instance Variables default value  demo :");
  System.out.println(b);
   System.out.println(s);
  System.out.println(i);
   System.out.println(l);
  System.out.println(f);
   System.out.println(d);
  System.out.println(ch);
   System.out.println(b1);
   System.out.println(f1);
  
 }

 void show2() {
  System.out.println("Integer literal demo :");
   int a = 12;
  int b = 012;
   int c = 0x12;
   int c1 = 0x12a;
  byte d = 012;
// when you will check .class file using decompiler you will find it has been replaced
as follow: //int a = 12;
               // int b = 10;
                //int c = 18;
               // int c1 = 298;
               // byte d = 10;                System.out.println(a);
   System.out.println(b);
   System.out.println(c);
   System.out.println(c1);
  System.out.println(d);
  }

 void show3() {
   System.out.println("Floating point literal demo :");
   float f1 = 99.9f;
   double d1 = 9.9e-9;
   double d2 = 9.9E+9;
// when you will check .class file using decompiler you will find it has been replaced
as follow:    //float f1 = 99.9F;
              //double d1 = 9.8999999999999993E-009D;
              //double d2 = 9900000000D;
  System.out.println(f1);
  System.out.println(d1);
  System.out.println(d2);
  }

  void show4() {
    System.out.println("Character literal demo :");
   char ch1 = 'A';
   int x1 = 'A';
   char ch2 = ' ';
   int x2 = ' ';
   char ch3 = '1';
    int x3 = '1';
  char ch = ' ';
// when you will check .class file using decompiler you will find it has been replaced
as follow:    // char ch1 = 'A';
             //  int x1 = 65; //ASCII value according to type we have used for value
             //  char ch2 = ' ';
             //  int x2 = 32;
             //  char ch3 = '1';
              // int x3 = 49;
              // char ch = ' ';
   System.out.println(ch1);
   System.out.println(x1);
  System.out.println(ch2);
   System.out.println(x2);
   System.out.println(ch3);
   System.out.println(x3);
   System.out.println(ch);
  }

 void show5() {
   System.out.println("Boolean literal demo :");
   boolean bb1 = false;
   boolean bb2 = true;
   boolean bb3 = true;

  System.out.println(bb1);
   System.out.println(bb2);
   System.out.println(bb3);
 }

  void show6() {
  System.out.println("string literal demo :");
   String str1 = "";
  String str2 = "123 abc + ";
  String str3 = "      1";
// when you will check .class file using decompiler you will find it has been replaced
as follow: //System.out.println((new StringBuilder("Str1=")).append(str1).toString());
        //System.out.println(str1.length());
       // System.out.println((new StringBuilder("Str2=")).append(str2).toString());
       // System.out.println(str2.length());
        //System.out.println((new StringBuilder("Str3=")).append(str3).toString());
       // System.out.println(str3.length());
  System.out.println("Str1=" + str1);
  System.out.println(str1.length());
  System.out.println("Str2=" + str2);
   System.out.println(str2.length());
  System.out.println("Str3=" + str3);
  System.out.println(str3.length());
  }
 }

class lab2 {
  public static void main(String as[]) {

  hello h = new hello();
   h.show1();
  h.show2();
  h.show3();
   h.show4();
  h.show5();
   h.show6();
 }

}

Output :

Instance variables default  demo :
0
0
0
0
0.0
0.0
false
10.9

Integer literal demo :
12
10
18
298
10

Floating point literal demo :
99.9
9.9E-9
9.9E9

Character literal demo :
A
65

32
1
49

Boolean literal demo :
false
true
true

string literal demo :
Str1=
0
Str2=123 abc +
10
Str3=      1
7