conversion decimal to hexadecimal

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

@@ -0,0 +1,26 @@
+package src.main.java.com.conversions;
+
+import java.math.BigInteger;
+
+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");
+
+    /**
+     * This method converts and decimal number to a Hexadecimal number
+     * @param decimalStr
+     * @return hexadecimal number
+     */
+    public String decimalToHex(String decimalStr){
+        BigInteger decimal = new BigInteger(decimalStr);
+
+        int rem;
+        String hex = "";
+        while(decimal.compareTo(BigInteger.ZERO) > 0) {
+            rem = decimal.mod(valueHex).intValueExact();
+            hex = hexChars[rem] + hex;
+            decimal = decimal.divide(valueHex);
+        }
+        return hex;
+    }
+}

src/test/java/com/conversions/DecimalToHexadecimalTest.java

@@ -0,0 +1,17 @@
+package src.test.java.com.conversions;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class DecimalToHexadecimalTest {
+
+    @Test
+    public void testDecimalToHexadecimalTest() {
+        DecimalToHexadecimal decimalToHexadecimal = new DecimalToHexadecimal();
+        Assert.assertEquals("Incorrect Conversion", "F", decimalToHexadecimal.decimalToHex("15"));
+        Assert.assertEquals("Incorrect Conversion", "121", decimalToHexadecimal.decimalToHex("289"));
+        Assert.assertEquals("Incorrect Conversion", "AAAAAAAAAAAAAAAAAA1", decimalToHexadecimal.decimalToHex("50371909150609548946081"));
+        Assert.assertEquals("Incorrect Conversion", "A", decimalToHexadecimal.decimalToHex("10"));
+        Assert.assertEquals("Incorrect Conversion", "8B2F", decimalToHexadecimal.decimalToHex("35631"));
+    }
+}