file renames

HelloWorld.java → 01HelloWorld.java

@@ -1,5 +1,5 @@
 class HelloWorld {
 	public static void main(String[] args) {
-		System.out.println("Hello! World.");
+		System.out.println("Hello, World !");
 	}
 }

02JavaDataTypes.java

@@ -0,0 +1,29 @@
+class JavaDataTypes {
+
+    public static void main(String args[]) {
+
+        boolean bool = true; // Holds values "True" or "False".
+
+        byte b = 127; // Ranges from -128 to 127.
+
+        short s = 32_767; // Its value-range lies between -32,768 to 32,767.
+
+        int i = 38299; /*
+                        * Its value-range lies between - 2,147,483,648 (-2^31) to 2,147,483,647
+                        * (2^31-1).
+                        */
+
+        long l = 89403938849383l; /*
+                                   * Its value-range lies between -9,223,372,036,854,775,808(-2^63) to
+                                   * 9,223,372,036,854,775,807(2^63 -1).
+                                   */
+
+        float f = 256.5f; // 32-bit
+
+        double d = 3489.78; // 64-bit
+
+        char c = '$'; // 16-bit Unicode character Its value-range lies between '\u0000' (or 0) to
+                      // '\uffff' (or 65,535 inclusive).
+
+    }
+}

JavaTypeCasting.java

@@ -1,20 +1,21 @@
-class JavaTypeCasting{
-public static void main(String args[]){
+class JavaTypeCasting {
+    public static void main(String args[]) {
 
-    byte b1=10;
-    byte b2=30;
-    int a = b2; //Implicite type casting or conversion.
+        byte b1 = 10;
+        byte b2 = 30;
+        int a = b2; // Widening || Implicite type casting or conversion.
 
-    System.out.println(a);
+        System.out.println(a);
 
-    float f=1729.89f;
-    int i=(int) f; //Explicite type casting.
+        float f = 1729.89f;
+        int i = (int) f; // Narrowing || Explicite type casting.
 
-    System.out.println(i);
+        System.out.println(i);
 
-    int result= b1*b2; //Type promotion. (As the multiplication operation gives result beyond the range of byte hence it stores it into int.)
+        int result = b1 * b2; // Type promotion. (As the multiplication operation gives result beyond the
+                              // range of byte hence it stores it into int.)
 
-    System.out.println(result);
-}
+        System.out.println(result);
+    }
 
 }