Wrapper classes : Wrapper classes « Utility Classes « SCJP

1. SCJP
2. Utility Classes
3. Wrapper classes

xxxValue() from primitive wrappers takes no arguments, returns a primitive

parseXxx() from primitive wrappers takes a String, returns a primitive

valueOf() from primitive wrappers takes a String, returns a wrapped object

Wrapper constructors can take a String or a primitive, except for Character, which can only take a char.

Radix refers to bases (typically) other than 10; octal is radix = 8, hex = 16.

Boxing allows you to convert primitives to wrappers or to convert wrappers to primitives automatically.


public class MainClass {
 public static void main(String args[]) {
  Boolean b1 = new Boolean("TRUE");
  Boolean b2 = new Boolean("FALSE");
  System.out.println(b1.toString()+" or "+b2.toString());
  for(int j=0;j<16;++j){
   System.out.print(Character.forDigit(j,16));
  }
  

  Integer i = new Integer(Integer.parseInt("ef",16));
  Long l = new Long(Long.parseLong("abcd",16));
  long m=l.longValue()*i.longValue();
  System.out.println(Long.toString(m,8));
  System.out.println(Float.MIN_VALUE);
  System.out.println(Double.MAX_VALUE);
 }
}

true or false
0123456789abcdef50062143
1.4E-45
1.7976931348623157E308