Q:

Convert decimal to binary and vice-versa in Java

I'm trying to learn Java, so I'm doing a few exercises from a programmer project idea book. This exercise requires that the program be able to convert a decimal number to binary and vice versa, like so:

Please enter the binary/decimal number to convert:9783569
100101010100100100010001

Please enter the binary/decimal number to convert:100101010100100100010001
9783569

Here's the code I came up with:
import java.util.Scanner;

public class BinaryToDecimalAndBackConverter{

    static String convertDecimalToBinary(String decimal){
            int integer = Integer.valueOf(decimal);
            String result = new String();

            while(integer > 0){
                result+=String.valueOf(integer%2);
                integer/=2;
            }

            result = new StringBuffer(result).reverse().toString();
            return result;
    }
    static int convertBinaryToDecimal(String binary){
            int result = 0;

            for(int reverseCounter = 0; reverseCounter < binary.length(); reverseCounter++){
                char currentChar = binary.charAt(binary.length() - reverseCounter - 1);
                int numericValue = Character.getNumericValue(currentChar);
                result+=Math.pow(2, reverseCounter) * numericValue;
//              System.out.println(Math.pow(2, reverseCounter) * Character.getNumericValue(binary.charAt(binary.length() - reverseCounter - 1)) + " reverseCounter " + reverseCounter);
            }

            return result;
    }
    static String isDecimalOrBinary(String input){
        for(int counter = 0; counter < input.length(); counter++){
            if(input.charAt(counter) != '0' && input.charAt(counter) != '1'){
                return "decimal";
            }
        }

        return "binary";
    }
    public static void main(String[] args){
        Scanner inputScanner = new Scanner(System.in);

        System.out.print("Please enter the binary/decimal number to convert:");
        String input = inputScanner.nextLine();

        switch(isDecimalOrBinary(input)){
            case "decimal":
                System.out.println(convertDecimalToBinary(input));
            break;
            case "binary":
                System.out.println(convertBinaryToDecimal(input));
            break;
        }
    }
}

A:

In addition to @Francesco Pitzalis's answer...
String concatenation
String result = new String();

This is never required as Strings are immutable in Java. If you find yourself using it to append String values, then you should be using StringBuilder (the faster, non-synchronized version of StringBuffer, which is usually recommended unless you require the multi-threading safety of the latter):
StringBuilder result = new StringBuilder();
// ...
result.append(integer % 2); // add some spaces for readability
// ...
return result.reverse().toString();

try-with-resources
// don't forget to close the Scanner
inputScanner.close();

Since you are on Java 7 at least (from the use of String in switch), you should be using try-with-resources to safely and efficiently manage the underlying I/O resource used by your Scanner instance:
try (Scanner scanner = new Scanner(System.in)) {
    // ...
}

Choices and enums
On a related note to your isDecimalOrBinary() method (which @Francesco Pitzalis's answer made a very good point), the return type can also be modeled as an enum should you still choose to keep it:
enum ValueType {
    DECIMAL, BINARY;

    public static ValueType parse(String value) {
        // ...
    }
}

This eliminates the possibility of typos in your expected String return values, e.g. when you return "decimal" but are wrongly checking for "Decimal" from calling the method.

