Removed usage of BigInteger constructor for constants

Author: abhijay94

src/main/java/com/conversions/BinaryToHexadecimal.java

@@ -36,7 +36,7 @@ public String binToHex(String binStr) {
         String hex = "";
 
         int currentBit;
-        BigInteger tenValue = new BigInteger("10");
+        BigInteger tenValue = BigInteger.valueOf(10);
         while (binary.compareTo(BigInteger.ZERO) != 0) {
             // to store decimal equivalent of number formed by 4 decimal digits
             int code4 = 0;

src/main/java/com/conversions/DecimalToHexadecimal.java

@@ -4,7 +4,7 @@
 
 public class DecimalToHexadecimal {
     private static final char[] hexChars = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
-    private static final BigInteger valueHex = new BigInteger("16");
+    private static final BigInteger valueHex = BigInteger.valueOf(16);
 
     /**
      * This method converts and decimal number to a Hexadecimal number

src/main/java/com/conversions/DecimalToOctal.java

@@ -4,7 +4,7 @@
 
 public class DecimalToOctal {
     private static final char[] octalChars = {'0', '1', '2', '3', '4', '5', '6', '7'};
-    private static final BigInteger valueOctal = new BigInteger("8");
+    private static final BigInteger valueOctal = BigInteger.valueOf(8);
 
     /**
      * This method converts and decimal number to a octal number