## Java converting int to hex and back again

decimal to hexadecimal using stack in java

java integer to hex string with leading zeros

binary to hexadecimal in java

java print int as hex

java int to hex byte

java program to convert decimal to binary, octal and hexadecimal

java hex

I have the following code...

int Val=-32768; String Hex=Integer.toHexString(Val);

This equates to `ffff8000`

int FirstAttempt=Integer.parseInt(Hex,16); // Error "Invalid Int" int SecondAttempt=Integer.decode("0x"+Hex); // Error "Invalid Int"

So, initially, it converts the value -32768 into a hex string ffff8000, but then it can't convert the hex string back into an Integer.

In `.Net`

it works as I'd expect, and `returns -32768`

.

I know that I could write my own little method to convert this myself, but I'm just wondering if I'm missing something, or if this is genuinely a bug?

It overflows, because the number is negative.

Try this and it will work:

int n = (int) Long.parseLong("ffff8000", 16);

**Convert Integer to Hex String in Java,** toHexString() method in Java converts Integer to hex string. Let's say the following are our integer values. int val1 = 5; int val2 = 7; int val3 = 13; Convert the above int values to hex string. You should be aware that Java’s parseInt method is actally a bunch of code eating “false” hex : if you want to translate -32768, you should convert the absolute value into hex, then prepend the string with ‘-‘.

int val = -32768; String hex = Integer.toHexString(val); int parsedResult = (int) Long.parseLong(hex, 16); System.out.println(parsedResult);

That's how you can do it.

The reason why it doesn't work your way: `Integer.parseInt`

takes a signed int, while `toHexString`

produces an unsigned result. So if you insert something higher than `0x7FFFFFF`

, an error will be thrown automatically. If you parse it as `long`

instead, it will still be signed. But when you cast it back to int, it will overflow to the correct value.

**Java program to convert decimal to hexadecimal,** There are two following ways to convert Decimal number to hexadecimal import java.util. nextInt(); // calling method toHexString() String str = Integer. Does java.lang.Integer lack a pair of methods to convert integers to strings using hexadecimal digits and back into integers? The obvious answer is toHexString and decode/valueOf. However, decode and valueOf both want negative values to have an explicit negative sign. As a result, Integer.valueOf(Integer.toHexString(-1), 16) throws an exception.

**Converting to/from hexadecimal in Java,** How to convert from decimal to hex (and vice versa) in Java. 0x before them. For example, 0x100 means 'the hexadecimal number 100' (=256 in decimal). I just realised now that to actually solve the given test cases, it is to convert hex to int, not the other way around. However, the question title that says "Java Convert integer to hex integer" has led many answers including mine and the most upvoted one to converting int to hex. – Wit Jun 23 '17 at 1:41

It's worth mentioning that Java 8 has the methods `Integer.parseUnsignedInt`

and `Long.parseUnsignedLong`

that does what you wanted, specifically:

`Integer.parseUnsignedInt("ffff8000",16) == -32768`

The name is a bit confusing, as it parses a signed integer from a hex string, but it does the work.

**How to convert integer to hexadecimal value?,** package com.java2novice.wrapper.integer;. public class MyIntegerToHex {. public static void main(String a[]){. Integer i = new Integer( 20 );. String hex = Integer. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Learn more use Java to convert ANY file to hex and back again

Try using BigInteger class, it works.

int Val=-32768; String Hex=Integer.toHexString(Val); //int FirstAttempt=Integer.parseInt(Hex,16); // Error "Invalid Int" //int SecondAttempt=Integer.decode("0x"+Hex); // Error "Invalid Int" BigInteger i = new BigInteger(Hex,16); System.out.println(i.intValue());

**Convert Hex to ASCII and ASCII to Hex,** Many times we do need to convert the string values ASCII from/to Hex format. Convert String to char array; Cast it to Integer; Use Integer. “//howtodoinjava.com” to first in hex format, and then convert that hex string to again in ASCII value. Java Convert Decimal to Hexadecimal. We can convert decimal to hexadecimal in java using Integer.toHexString() method or custom logic. Java Decimal to Hex conversion: Integer.toHexString() The Integer.toHexString() method converts decimal to hexadecimal. The signature of toHexString() method is given below:

**Java exercises: Convert a decimal number to hexadecimal number ,** Write a Java program to convert a decimal number to hexadecimal number. int dec_num, rem; String hexdec_num=""; /* hexadecimal number It's worth mentioning that Java 8 has the methods Integer.parseUnsignedInt and Long.parseUnsignedLong that does what you wanted, specifically: Integer.parseUnsignedInt("ffff8000",16) == -32768. The name is a bit confusing, as it parses a signed integer from a hex string, but it does the work.

**Program for Hexadecimal to Decimal,** import java.io.*;. class GFG. {. // Function to convert hexadecimal to decimal. static int hexadecimalToDecimal(String hexVal). {. int len = hexVal.length();. Java Convert Hexadecimal to Decimal. We can convert hexadecimal to decimal in java using Integer.parseInt() method or custom logic. Java Hexadecimal to Decimal conversion: Integer.parseInt() The Integer.parseInt() method converts string to int with given redix. The signature of parseInt() method is given below:

**How to convert String to Hex in Java,** toHexString and Integer.parseInt(hex, 16) to convert the String to Hex and vice versa. The idea is convert String <==> Decimal < Here is my attempt at converting hex strings to byte arrays and converting byte arrays to hex strings: net.coderodde.util.ByteStringConverter. package net.coderodde.util; import java.util.Scanner; public class ByteStringConverter { /** * Converts the given byte array to its textual hex representation.

##### Comments

- possible duplicate of Java negative int to hex and back fails
- Just a hint: As convention variable names start with a lower case character:
`int firstAttempt = 5;`

- Thanks roni, that seems to be the best solution. Although it still seems odd that Int.parseInt doesn't work as I'd expect.
- ffff8000 doesn't fit into an int (bigger then max int), this is a positive number (it is a string so it negative only if it has minus)
- It's because parseInt takes a signed int and toHexString produces an unsigned result (see my answer)...
- Thanks u saved my day :)
- @roni, what if hex is of String value like
`String Hex=Integer.toHexString("xyz");`

how to get back string from the hex as "xyz" `// Accumulating negatively avoids surprises near MAX_VALUE`

-> but it introduces surprises lower 0 ^^