Primitive types bookmark

			
/**
 * Show how to use primitive types
 */
public void primitiveTypes() {
	// this is an integer, but should not be
	// used as a numerical value
	// chars represent character symbols
	char character = 0;

	// this is a byte, it is unsigned
	byte veryShortInt = 0;

	// this is a short integer, it is signed
	short shortInt = 0;

	// it's a normal range integer, it is signed
	int normalInt = 0;

	//  it's a wide range integer; it is signed,
	//  notice that to be a long, you have to put
	//  a "l" after the number
	long longInt = 022222222222222222l;

	// This is a floating point number
	float floatingPoint = 0;

	// this is a floating point number with a
	// wide range
	double bigFloatingPoint = 0;

	// this is a boolean (can have true or false as
	// a value)
	boolean aBooleanExample;
}

Autoboxing bookmark

			
/**
 * Shows how primitive types can be "boxed" (automatically cast) to Objects
 */
public void autoBoxing() {
	char character = 0;
	byte veryShortInt = 0;
	short shortInt = 0;
	int normalInt = 0;
	long longInt = 0l;

	float floatingPoint = 0;
	double bigFloatingPoint = 0;

	boolean aBooleanExample = true;

	// Object style

	Byte byteSample = veryShortInt;
	Short shortSample = shortInt;
	Integer intSample = normalInt;
	Long longSample = longInt;

	Float floatSample = floatingPoint;
	Double doubleSample = bigFloatingPoint;
	Boolean booleanSample = aBooleanExample;
}

Dates bookmark

			public Date stringToDate(){
    String format = "yyyy/MM/dd - HH:mm:ss.SSS";
	SimpleDateFormat simpleDateFormat = new SimpleDateFormat(format);
	String stringInput = "2014/05/25 - 16:58:10.302";
	try {
		Date date = simpleDateFormat.parse(stringInput);
		return date;
		//Use the date Object
	} catch (ParseException e) {
		e.printStackTrace();
	}
	return null;
}

public String dateToString(Date date){
    String format = "yyyy/MM/dd - HH:mm:ss.SSS";
	SimpleDateFormat simpleDateFormat = new SimpleDateFormat(format);
	String stringResult = simpleDateFormat.format(date);
	return stringResult;
}

Strings bookmark

			String firstString = "Sample String";
String secondString = "Second String";

System.out.println("Testing concatenation");
String concatResult = firstString + " " + secondString;
System.out.println(concatResult);

System.out.println("Testing replacement");
concatResult = concatResult.replaceAll("St" , "" );
System.out.println(concatResult);

//Full spec here
//http://docs.oracle.com/javase/7/docs/api/java/util/Formatter.html
String formattedString = String.format("%tD", new Date());
System.out.println(formattedString);


System.out.println("Testing immutability");
stringImmutability(concatResult);
System.out.println(concatResult);

//StringBuilder is a class to operate concatenation over Strings
StringBuilder sb = new StringBuilder(concatResult);
System.out.println("Testing mutability of other objects");
objectsMutability(sb);
System.out.println(String.valueOf(sb)); //Obtain a string representation

StringBuilder bookmark

			//StringBuilder is a class to operate concatenation over Strings
StringBuilder sb = new StringBuilder("test");
sb.append(" java");
System.out.println(sb.toString()); //Obtain a string representation