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Dealing with nulls

    UtilFactory.convertNull

Java - comparing strings

    Use == for primitive data types like int
    If (mystring == null)

    Use the equals() method to compare objects
    Use .equals for strings : if (a.equals(“cat”))

Java - Converting int to string

    String myString = Integer.toString(my int value)     or
    String str = "" + i

Java - Converting String to int

    int i = Integer.parseInt(str);    
    or    
    int i = Integer.valueOf(str).intValue();          

 

double to String :

    String str = Double.toString(i);

long to String :

    String str = Long.toString(l);

 

float to String :

    String str = Float.toString(f);

 

String to double :

    double d = Double.valueOf(str).doubleValue();

 

String to long :

   long l = Long.valueOf(str).longValue();   or   long l = Long.parseLong(str);

String to float :

    float f = Float.valueOf(str).floatValue();

decimal to binary :

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

decimal to hexadecimal :

    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());
        }
    }         

hexadecimal (String) to integer :

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

ASCII code to String

    int i = 64;
    String aChar = new Character((char)i).toString();

integer to ASCII code (byte)

    char c = 'A';         
    int i = (int) c; // i will have the value 65 decimal

integer to boolean

    b = (i != 0);

boolean to integer

    i = (b)?1:0;