Thread: char.toHexString();

Because toHexString() is a static method of the Integer class, not of the Character class. Check out the API.

It's sort of similar to why you can do Character.toUpperCase(int) but not Integer.toUpperCase(int). It's simply a matter of to which class those methods belong.

Java Platform SE 6

Did you look at the API? That method doesn't change the int you pass into it (it actually can't do that for multiple reasons). Instead, that method returns a String. Store that String and print that instead of printing the original value.

API means Application Programming Interfaces

The Java API is the set of classes included with the Java Development Environment. It is like the official documentation for a class.

Please see - Java Platform SE 6

Originally Posted by SPACE MONKEY

The reason I am delving into this is because I am reading Ivor Hortons "Beginning Java 2 JDK 5th Edition"

Can anyone tell me, is this book using at least the most recent "MAJOR" rewrite of Java? Or am I going to come a cropper with some of the stuff in there?

From wikipedia: J2SE 5.0 entered its end-of-life on April 8, 2008 and is no longer supported by Sun as of November 3, 2009.

The most recent version is Java SE 6 Update 24.

Your book won't contain anything that's necessarily wrong, but it wouldn't hurt to use a more recent version.

Java version history - Wikipedia, the free encyclopedia

Dear All:

Thanks for the help, the AIP is very helpful. I have to now try and understand how it is structured so I can find stuff easier, or just google it.

This is the code that works. I am concerned because I am not sure why I was told the .

Integer.toHexString(convert1);

would not work.
from the AIP the information type on the Left Hand Side (LHS) indicated a double value was required, so I thought I had to convert to a double. Now I have no idea what the information on the LHS column is there for. No doubles where killed in the making of this line of code.

String sletter1 = Integer.toHexString(convert1);

So if someone can explain that to me it would be useful.

 
public class LetterConversion{
public static void main(String [] args)
{
//From page 62 hortons, got a who JDK 5th. 
char letter1 = 'A', letter2 = 'B', letter3 = 'C';
 
System.out.println("So far we have: " + letter1 +" " + letter2 + " " + letter3);
 
// Converting the characters into int.
int convert1 = letter1, convert2 = letter2, convert3 = letter3;
 
System.out.println("Now we have changed the Charicters to there Integer counterparts: " \n
+ convert1 + " " + convert2 + " " + convert3);
 
//converting the int to Hex String 
System.out.println("Now we use the \"Integer.toHexString()\" command, and we get!");
String sletter1 = Integer.toHexString(convert1); 
String sletter2 = Integer.toHexString(convert2);
String sletter3 = Integer.toHexString(convert3);
 
System.out.println("Letter a is now: " + sletter1);
System.out.println("Letter b is now: " + sletter2);
System.out.println("Letter c is now: " + sletter3);
}}

One of the lessons I am learning is the distinction between primitive types and not so primitive types like Strings. I am not there yet but I know that the difference exists.

I am assuming the String, not being primitive needs/has methods that are required for Strings to be manipulated, where as conversions from "Char" to "Int" are so much simpler. What type of type "Char" is I am not yet sure.

I am editing this post, because I now know I have no idea what I am talking about with the previous two sentences.

Thanks again for all your help. I am going back to look at my original code to compare.

I'm not sure what your question is. Integer.toHexString() takes an int and returns a String. Where do you see that a double is required?

Well, Long is yet another class in the API, but that still doesn't explain where you got the double requirement. Double is another class (these are all primitive wrapper classes).

I'm not really sure what you're asking. That just links to the main part of the API. The column on the left provides links to all of the java packages and classes.

Are you talking about a specific class in the API?

If you want to provide a link to a specific class or function, I'd recommend using your browser's "open in new tab" or "copy link location" feature with that class or method. Then you'll get something like this:Math (Java Platform SE 6)

But if I understand your question, the column on the left contains the type of field or method. Basically, it tells you how that field or method was declared, what type of variable it is (or what type a method returns), whether the method is static, abstract, or something else, etc.