How to convert map to List in java?

Assuming map is your instance of Map :
map.values() will return a Collection containing all of the map's values
map.keys() will return a Set containing all of the map's keys
map.entrySet() will return a Set containing all map key value pairs.

Get list of keys

List<String> list = new ArrayList<String>(map.keySet());

Get list of values

List<String> list = new ArrayList<String>(map.values());

Conversion from decimal to binary

You can convert a decimal to binary using toBinaryString() method of Integer wrapper class as follows.

int i = 42;
String binstr = Integer.toBinaryString(i);


Conversion from integer to hexadecimal and vice-versa

You can convert a hexadecimal to integer using two different methods as shown below:
int i = Integer.valueOf("B8DA3", 16).intValue();

   or

int i = Integer.parseInt("B8DA3", 16);  

You can convert a decimal to binary using three different methods as shown below:

int i = 42;
String hexstr = Integer.toString(i, 16);

or

String hexstr = Integer.toHexString(i);

or (with leading zeroes and uppercase)

public class Hex {
public static void main(String args[]){
int i = 42;
System.out.print
(Integer.toHexString( 0x10000 | i).substring(1).toUpperCase());
}
}


Convert String to byte array

This example shows how to do it:

String stringToConvert = "This String is 76 characters long and will be converted to an array of bytes";
        
byte[] theByteArray = stringToConvert.getBytes();
        

Convert from byte array to string

This the function to convert byte array to string:

//eg. byte[] byteArray = new byte[] {87, 79, 87, 46, 46, 46};
public static String convertByteArrayToString(byte[] byteArray) {
       
       String value = new String(byteArray);
       
       return value;
   }

Converting an integer to binary string - Binary.java

/*************************************************************************
 *  Compilation:  javac Binary.java
 *  Execution:    java Binary n
 *  
 *  Prints out n in binary.
 * 
 *  % java Binary 5
 *  101
 *
 *  % java Binary 106
 *  1101010
 *
 *  % java Binary 0
 *  0
 * 
 *  % java Binary 16
 *  10000
 *
 *  Limitations
 *  -----------
 *  Does not handle negative integers.
 *
 *  Remarks
 *  -------
 *  could use Integer.toBinaryString(N) instead.
 *
 *************************************************************************/

public class Binary { 
    public static void main(String[] args) { 

        // read in the command-line argument
        int n = Integer.parseInt(args[0]);

        // set v to the largest power of two that is <= n
        int v = 1;
        while (v <= n/2) {
            v = v * 2;
        }
  
        // check for presence of powers of 2 in n, from largest to smallest
        while (v > 0) {

            // v is not present in n 
            if (n < v) {
                System.out.print(0);
            }

            // v is present in n, so remove v from n
            else {
                System.out.print(1);
                n = n - v;
            }

            // next smallest power of 2
            v = v / 2;
        }

        System.out.println();

    }

}

Though written a program, we can use inbuilt lib of java - See here.